Regioselectively substituted cellulose esters and films made therefrom

ABSTRACT

Regioselectively substituted cellulose esters having a plurality of pivaloyl substituents and a plurality of aryl-acyl substituents are disclosed along with methods for making the same. Such cellulose esters may be suitable for use in films, such as +A optical films, and/or +C optical films. Optical films prepared employing such cellulose esters have a variety of commercial applications, such as, for example, as compensation films in liquid crystal displays and/or waveplates in creating circular polarized light used in 3-D technology.

FIELD OF THE INVENTION

This application relates generally to cellulose ester compositions,methods of making cellulose ester compositions, and optical filmsproduced therefrom.

BACKGROUND OF THE INVENTION

Cellulose esters such as cellulose triacetate (“CTA” or “TAC”),cellulose acetate propionate (“CAP”), and cellulose acetate butyrate(“CAB”), are used in a wide variety of films for the liquid crystaldisplay (“LCD”) industry. Most notable is their use as protective andcompensation films used in conjunction with polarizer sheets. Thesefilms can typically be made by solvent casting, and then be laminated toeither side of an oriented, iodinated polyvinyl alcohol (“PVOH”)polarizing film to protect the PVOH layer from scratching and moistureingress, while also increasing structural rigidity. When used ascompensation films (a.k.a., waveplates), they can be laminated with thepolarizer stack or otherwise included between the polarizer and liquidcrystal layers. The waveplates can act to improve the contrast ratio,wide viewing angle, and color shift performance of the LCD. Whilesignificant advances have been made in LCD technology, improvements arestill needed.

SUMMARY OF THE INVENTION

This application discloses a regioselectively substituted celluloseester comprising:

(a) a plurality of chromophore-acyl substituents; and

(b) a plurality of pivaloyl substituents,

wherein the cellulose ester has a hydroxyl degree of substitution(“DS_(OH)”) in the range of from about 0 to about 0.9,

wherein the cellulose ester has a pivaloyl degree of substitution(“DS_(Pv)”) in the range of from about 0.1 to about 1.2,

wherein the cellulose ester has a chromophore-acyl degree ofsubstitution (“DS_(Ch)”) in the range of from about 0.4 to about 1.6,and

wherein the regioselectivity is such that the sum of thechromophore-acyl degree of substitution at C2 and C3 (“C2DS_(Ch)” and“C3DS_(Ch)”) minus the chromophore-acyl degree of substitution at C6(“C6DS_(Ch)”) is between about 0.5 and about 1.6

wherein the chromophore-acyl is chosen from

-   -   (i) an (C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or        substituted by 1-5 R^(!);    -   (ii) a heteroaryl-acyl, wherein the heteroaryl is a 5- to        10-membered ring having 1- to 4-heteroatoms chosen from N, O, or        S, and wherein the heteroaryl is unsubstituted or substituted by        1-5 R¹;

-   -    wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is        unsubstituted or substituted by 1-5 R¹; or

-   -    wherein the heteroaryl is a 5- to 10-membered ring having 1-4        heteroatoms chosen from N, O or S, and wherein the heteroaryl is        unsubstituted or substituted by 1-5 R¹,    -   wherein each R¹ is independently chosen from nitro; cyano;        (C₁₋₆)alkyl; halo(C₁₋₆)alkyl; (C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl;        (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo, 5- to 10-membered        heteroaryl having 1-4 heteroatoms chosen from N, O, or S; or

The present invention also discloses compositions, films and liquidcrystalline displays (“LCD”) made with the regioselectively substitutedcellulose ester.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the present invention are described herein with referenceto the following figures, wherein:

FIG. 1(a) schematically depicts backlight passing through a pair ofcrossed polarizers with two conventional cellulose triacetate (“TAC”)films, each having an R_(e) of 0 nm and an R_(th) of −40 nm; FIG. 1(a)isprior art;

FIG. 1(b) depicts the calculated iso-contour plot of light transmissionor light leakage of the structure depicted in FIG. 1(a); FIG. 1(b) isprior art;

FIG. 2(a) schematically depicts backlight passing through a pair ofcrossed polarizers with a waveplate having an Nz of 0.5 and an R_(e) of270 nm disposed there between, where each polarizer comprises a zeroretardation TAC film adjacent to the waveplate;

FIG. 2(b) depicts the calculated iso-contour plot of light transmissionor light leakage of the structure depicted in FIG. 2(a);

FIG. 3(a) schematically depicts backlight passing through a bottompolarizer and a top polarizer, where the pair of polarizers are crossedand have one+A plate (R_(e)=137.5 nm) and one+C plate (R_(th)=100 nm)disposed therebetween, where each polarizer comprises a zero retardationTAC film adjacent to the +A plate and +C plate, respectively;

FIG. 3(b) depicts the calculated iso-contour plot of light transmissionor light leakage of the structure depicted in FIG. 3(a).

FIG. 4(a) shows a multilayer film according to the invention in an A-Bconfiguration.

FIG. 4(b) shows a multilayer film according to the invention in an A-B-Aconfiguration.

DETAILED DESCRIPTION

The present invention may be understood more readily by reference to thefollowing detailed description of the invention and the examplesprovided therein. It is to be understood that this invention is notlimited to the specific methods, formulations, and conditions described,as such may vary. It is also to be understood that the terminology usedherein is for the purpose of describing particular aspects of theinvention only and is not intended to be limiting.

Definitions

In this specification and in the claims that follow, reference will bemade to a number of terms, which shall be defined to have the followingmeanings.

Values may be expressed as “about” or “approximately” a given number.Similarly, ranges may be expressed herein as from “about” one particularvalue and/or to “about” or another particular value. When such a rangeis expressed, another aspect includes from the one particular valueand/or to the other particular value. Similarly, when values areexpressed as approximations, by use of the antecedent “about,” it willbe understood that the particular value forms another aspect.

As used herein, the terms “a,” “an,” and “the” mean one or more.

As used herein, the term “and/or,” when used in a list of two or moreitems, means that any one of the listed items can be employed by itselfor any combination of two or more of the listed items can be employed.For example, if a composition is described as containing components A,B, and/or C, the composition can contain A alone; B alone; C alone; Aand B in combination; A and C in combination, B and C in combination; orA, B, and C in combination.

As used herein, the terms “comprising,” “comprises,” and “comprise” areopen-ended transition terms used to transition from a subject recitedbefore the term to one or more elements recited after the term, wherethe element or elements listed after the transition term are notnecessarily the only elements that make up the subject.

As used herein, the terms “having,” “has,” and “have” have the sameopen-ended meaning as “comprising,” “comprises,” and “comprise” providedabove.

As used herein, the terms “including,” “includes,” and “include” havethe same open-ended meaning as “comprising,” “comprises,” and “comprise”provided above.

Regioselectively substituted cellulose esters suitable for use in makingoptical films can comprise a plurality of alkyl-acyl substituents and aplurality of aryl-acyl substituents. As used herein, the term “acylsubstituent” shall denote a substituent having the structure:

Such acyl groups in cellulose esters are generally bound to the pyranosering of the cellulose via an ester linkage (i.e., through an oxygenatom).

As used herein, the term “aryl-acyl” substituent shall denote an acylsubstituent where “R” is an aryl group. As used herein, the term “aryl”shall denote a univalent group formed by removing a hydrogen atom from aring carbon in an arene (i.e., a mono- or polycyclic aromatichydrocarbon). In some cases the aryl-acyl group is preceded by thecarbon units: For example, (C₅₋₆)aryl-acyl, (C₆₋₁₂)aryl-acyl, or(C₆₋₂₀)aryl-acyl. Examples of aryl groups suitable for use in variousembodiments include, but are not limited to, phenyl, benzyl, tolyl,xylyl, and naphthyl. Such aryl groups can be substituted orunsubstituted.

As used herein, the term “alkyl-acyl” shall denote an acyl substituentwhere “R” is an alkyl group. As used herein, the term “alkyl” shalldenote a univalent group formed by removing a hydrogen atom from anon-aromatic hydrocarbon, and may include heteroatoms. Alkyl groupssuitable for use herein can be straight, branched, or cyclic, and can besaturated or unsaturated. Alkyl groups suitable for use herein includeany (C₁₋₂₀), (C₁₋₁₂), (C₁₋₅), or (C₁₋₃) alkyl groups. In variousembodiments, the alkyl can be a C₁₋₅ straight chain alkyl group. Instill other embodiments, the alkyl can be a C₁₋₃ straight chain alkylgroup. Specific examples of suitable alkyl groups include, but are notlimited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,sec-butyl, tert-butyl, pentyl, hexyl, octyl, decyl, dodecyl,cyclopentyl, and cyclohexyl groups. Examples of alkyl-acyl groupsinclude acetyl, propionyl, butyroyl, and the like.

“Haloalkyl” means an alkyl substituent where at least one hydrogen isreplaced with a halogen group. The carbon units in the haloalkyl groupis often included; for example halo(C₁₋₆)alkyl. The haloalkyl group canbe straight or branched. Nonlimiting examples of haloalkyl includechloromethyl, trifluoromethyl, dibromoethyl and the like.

“Heteroaryl” means an aryl where at least one of the carbon units in thearyl ring is replaced with a heteroatom such as O, N, and S. Theheteroaryl is ring can be monocyclic or polycyclic. Often the unitsmaking up the heteroaryl ring system is include; for example a 5- to20-membered ring system. A 5-membered heteroaryl means a ring systemhaving five atoms forming the heteroaryl ring. Nonlimiting examples ofheteroaryl include pyridinyl, quinolinyl, pyrimidinyl, thiophenyl andthe like.

“Alkoxy” means alkyl-O— or an alkyl group terminally attached to anoxygen group. Often the carbon units are included; for example(C₁₋₆)alkoxy. Nonlimiting examples of alkoxy include Methoxy, ethoxy,propoxy and the like.

“Haloalkoxy” means alkoxy where at least one of the hydrogens is replacewith a halogent. Often the carbon units are included; for examplehalo(C₁₋₆)alkoxy. Nonlimiting examples of haloalkoxy includetrifluoromethoxy, bromomethoxy, 1-bromo-ethoxy and the like.

“Halo” means halogen such as fluoro, chloro, bromo, or iodo.

As used herein, the term “substantially” means within 5%. For example,substantially perpendicular means a range of from 84.5 degrees to 94.5degrees.

Substantially consumed means at least 95% or more has been consumed.

The term “naphthoyl” means

(1-naphthoyl) or

(2-naphthoyl).

A plasticizer is a substance added to a resin or polymer to improve theproperties of the resin or polymer such as improving the plasticity,flexibility and brittleness. Examples of plasticizers suitable for usein this invention include: Abitol E, Permalyn 3100, Permalyn 2085,Permalyn 6110, Foralyn 110, Admex 523, Optifilm Enhancer 400, Uniplex552, Uniplex 280, Uniplex 809, triphenylphosphate, tri(ethyleneglycol)bis(2-ethylhexoate), tri(ethyleneglycol)bis(n-octanoate), diethylphthalate, and combinations thereof.

“Degree of Substitution” is used to describe the substitution level ofthe substituents of the substituents per anhydroglucose unit (“AGU”).Generally, conventional cellulose contains three hydroxyl groups in eachAGU that can be substituted. Therefore, the DS can have a value between0 and 3. However, low molecular weight cellulose mixed esters can have atotal degree of substitution slightly above 3 from end groupcontributions. Low molecular weight cellulose mixed esters are discussedin more detail subsequently in this disclosure. Because DS is astatistical mean value, a value of 1 does not assure that every AGU hasa single substituent. In some cases, there can be unsubstitutedanhydroglucose units, some with two and some with three substituents,and more often than not the value will be a noninteger. Total DS isdefined as the average number of all of substituents per anhydroglucoseunit. The degree of substitution per AGU can also refer to a particularsubstituent, such as, for example, hydroxyl, acetyl, butyryl, orpropionyl. Additionally, the degree of substitution can specify whichcarbon unit of the anhydroglucose unit.

Numerical Ranges

The present description uses numerical ranges to quantify certainparameters relating to the invention. It should be understood that whennumerical ranges are provided, such ranges are to be construed asproviding literal support for claim limitations that only recite thelower value of the range as well as claim limitations that only recitethe upper value of the range. For example, a disclosed numerical rangeof 10 to 100 provides literal support for a claim reciting “greater than10” (with no upper bounds) and a claim reciting “less than 100” (with nolower bounds).

The present description uses specific numerical values to quantifycertain parameters relating to the invention, where the specificnumerical values are not expressly part of a numerical range. It shouldbe understood that each specific numerical value provided herein is tobe construed as providing literal support for a broad, intermediate, andnarrow range. The broad range associated with each specific numericalvalue is the numerical value plus and minus 60 percent of the numericalvalue, rounded to two significant digits. The intermediate rangeassociated with each specific numerical value is the numerical valueplus and minus 30 percent of the numerical value, rounded to twosignificant digits. The narrow range associated with each specificnumerical value is the numerical value plus and minus 15 percent of thenumerical value, rounded to two significant digits. For example, if thespecification describes a specific temperature of 62° F., such adescription provides literal support for a broad numerical range of 25°F. to 99° F. (62° F.+/−37° F.), an intermediate numerical range of 43°F. to 81° F. (62° F.+/−19° F.), and a narrow numerical range of 53° F.to 71° F. (62° F.+/−9° F.).

These broad, intermediate, and narrow numerical ranges should be appliednot only to the specific values, but should also be applied todifferences between these specific values. Thus, if the specificationdescribes a first pressure of 110 psia and a second pressure of 48 psia(a difference of 62 psi), the broad, intermediate, and narrow ranges forthe pressure difference between these two streams would be 25 to 99 psi,43 to 81 psi, and 53 to 71 psi, respectively.

Throughout this application, where patents or publications arereferenced, the disclosures of these references in their entireties areintended to be incorporated by reference into this application, to theextent they are not inconsistent with the present invention, in order tomore fully describe the state of the art to which the inventionpertains.

As mentioned above, films prepared from cellulose esters can be employedin liquid crystal displays (“LCD”). Generally, LCDs employ a polarizerstacking including a set of crossed polarizers. For a typical set ofcrossed polarizers used in an LCD, there can be significant lightleakage along the diagonals (leading to poor contrast ratio),particularly as the viewing angle is increased. Various optical filmscan be used to correct or “compensate” for this light leakage. Thesefilms can have certain well defined birefringences (or retardations)that vary depending on the type of liquid crystal cell used, since theliquid crystal cell itself will also impart a certain degree ofundesirable optical retardation that must be corrected. Some of thesecompensation films are easier to make than others, so compromises areoften made between performance and cost. Also, while most compensationand protective films are made by solvent casting, there is a push tomake more films by melt extrusion so as to eliminate the need to handleenvironmentally unfriendly solvents. Having a material with morecontrollable optical retardation, that can be made by both solvent andmelt casting, allows for greater flexibility in creating these films.

Optical films are commonly quantified in terms of birefringence whichis, in turn, related to the refractive index n. The refractive index cantypically be in the range of 1.4 to 1.8 for polymers in general, and canbe approximately 1.46 to 1.50 for cellulose esters. The higher therefractive index, the slower a light wave propagates through that givenmaterial.

For an unoriented isotropic material, the refractive index will be thesame regardless of the polarization state of the entering light wave. Asthe material becomes oriented, or otherwise anisotropic, the refractiveindex becomes dependent on material direction. For purposes of thepresent invention, there are three refractive indices of importance,denoted n_(x), n_(y), and n_(z), which correspond to the machinedirection (“MD”), the transverse direction (“TD”) and the thicknessdirection respectively. As the material becomes more anisotropic (e.g.,by stretching), the difference between any two refractive indices willincrease. This difference is referred to as the “birefringence.” Becausethere are many combinations of material directions to choose from, thereare correspondingly different values of birefringence. The two that arethe most common, namely the planar birefringence (or “in-plane”birefringence) Δ_(e) and the thickness birefringence (or “out-of-plane”birefringence) Δ_(th), are defined as:Δ_(e) =n _(x) −n _(y)  (1a)Δ_(th) =n _(z)−(n _(x) +n _(y))/2  (1b)

The birefringence Δ_(e) is a measure of the relative in-planeorientation between the MD and TD directions and is dimensionless. Incontrast Δ_(th) gives a measure of the orientation of the thicknessdirection, relative to the average planar orientation.

Another term often used with regards to optical films is the opticalretardation R. R is simply the birefringence times the thickness d, ofthe film in question. Thus,R _(e)=Δ_(e) d=(n _(x) −n _(y))d  (2a)R _(th)=Δ_(th) d=[n_(z)−(n _(x) +n _(y))/2]d  (2b)

Retardation is a direct measure of the relative phase shift between thetwo orthogonal optical waves and is typically reported in units ofnanometers (nm). Note that the definition of R_(th) varies among someauthors, particularly with regards to the sign (+/−), depending on howR_(th) is calculated.

Materials are also known to vary with regards to theirbirefringence/retardation behavior. For example, most materials whenstretched will exhibit a higher refractive index along the stretchdirection and a lower refractive index perpendicular to the stretch.This follows because, on a molecular level, the refractive index istypically higher along the polymer chain's axis and lower perpendicularto the chain. These materials are commonly termed “positivelybirefringent” and represent most standard polymers, including currentcommercial cellulose esters. Note that, as we will describe later, apositively birefringent material can be used to make either positive ornegative birefringent films or waveplates.

To avoid confusion, the birefringence behavior of the polymer moleculeitself will be referred to as the “intrinsic birefringence” and is aproperty of the polymer. From a material optics standpoint, intrinsicbirefringence is a measure of the birefringence that would occur if thematerial was fully stretched with all chains perfectly aligned in onedirection (for most polymers this is a theoretical limit since they cannever be fully aligned). For purposes of the present invention, it alsoprovides a measure of the sensitivity of a given polymer to a givenamount of chain orientation. For example, a sample with high intrinsicbirefringence is going to exhibit more birefringence during filmformation than a sample with low intrinsic birefringence, even thoughthe relative stress levels in the film are approximately the same.

Polymers can have positive, negative, or zero intrinsic birefringence.Negative intrinsic birefringent polymers exhibit a higher refractiveindex perpendicular to the stretch direction (relative to the paralleldirection). Certain styrenics and acrylics can have negative intrinsicbirefringent behavior due to their rather bulky side groups. Dependingon composition, some cellulose esters having aromatic ring structurescan exhibit negative intrinsic birefringence as well. Zero intrinsicbirefringence, in contrast, is a special case and represents materialsthat show no birefringence with stretching and thus have a zerointrinsic birefringence. Such materials can be ideal for certain opticalapplications as they can be molded, stretched, or otherwise stressedduring processing without showing any optical retardation or distortion.

The actual compensation film(s) that is/are used in an LCD can take on avariety of forms including biaxial films where all three refractiveindices differ and two optical axes exist, and uniaxial films havingonly one optical axis where two of the three refractive indices are thesame. There are also other classes of compensation films where theoptical axes twist or tilt through the thickness of the film (e.g.,discotic films), but these are generally of lesser importance.Generally, the type of compensation film that can be made is limited bythe birefringence characteristics of the polymer (i.e., positive,negative or zero intrinsic birefringence). A few examples are describedbelow.

In the case of uniaxial films, a film having refractive indices suchthatn _(x) >n _(y) =n _(z) “+A” optical film  (3a)

is denoted as a “+A” optical film. In such films, the x-direction(machine direction) of the film has a high refractive index, whereas they and thickness directions are approximately equal in magnitude (andlower than n_(x)). This type of film is also referred to as a positiveuniaxial crystal structure with the optic axis along the x-direction.Such films can be made by uniaxially stretching a positive intrinsicbirefringent material using, for example, a film stretcher.

In contrast, a “−A” uniaxial film is defined asn _(x) <n _(y) =n _(z) “−A” optical film  (3b)

where the x-axis refractive index is lower than the other directions(which are approximately equal). One method for making a −A optical filmis to stretch a negative intrinsic birefringent polymer or, alternately,by coating a negatively (intrinsic) birefringent liquid crystal polymeronto a surface such that the molecules are lined up in a preferreddirection (for example, by using an underlying etched orientationlayer).

In terms of retardation, “+A” optical films have the followingrelationship between R_(e) and R_(th), shown in (3c):R _(th) =−R _(e)/2 “±A” optical films  (3c)

Another class of uniaxial optical films is the C optical film which canalso be “+C” or “−C”. The difference between a C and an A optical filmis that, in C optical films, the unique refractive index (or opticalaxis) is in the thickness direction as opposed to in the plane of thefilm. Thus,n _(z) >n _(y) =n _(x) “+C” optical film  (4a)n _(z) <n _(y) =n _(x) “−C” optical film  (4b)

C optical films can be produced by taking advantage of the stresses thatform during solvent casting of a film. Tensile stresses are generallycreated in the plane of the film due to the restraint imposed by thecasting belt, which are also equi-biaxial stretched in nature. Thesetend to align the chains in the plane of the film resulting in −C or +Cfilms for positive and negative intrinsic birefringent materialsrespectively. As many cellulose ester films used in displays are solventcast, and many are essentially positive birefringent, then it isapparent that solvent cast cellulose esters normally only produce −Coptical films. These films can also be uniaxially stretched to produce+A optical films (assuming the initial as-cast retardation is very low).

Besides uniaxial optical films, it is also possible to use biaxialoriented films. Biaxial films are quantified in a variety of waysincluding simply listing the 3 refractive indices n_(x), n_(y) and n_(z)in the principal directions (along with the direction of these principalaxes). Generally, n_(x)≠n_(y)≠n_(z).

One specific biaxial oriented film has unique optical properties tocompensate light leakage of a pair of crossed polarizers or in-planeswitching (“IPS”) mode liquid crystal displays. The optical film has aparameter Nz in the range of from about 0.4 to about 0.9, or equalsabout 0.5, where Nz is defined asNz=(n _(x) −n _(z))/(n _(x) −n _(y))  (5)

This parameter gives the effective out-of-plane birefringence relativeto the in-plane birefringence. Nz can be chosen to be about 0.5 whenused as a compensation film for a pair of crossed polarizers. When Nz isabout 0.5, the corresponding out-of-plane retardation, R_(th), equalsabout 0.0 nm.

To show the optical film's compensation effect, the following lighttransmission or leakage of a pair of crossed polarizers with and withoutcompensation films is calculated by computer simulation.

FIG. 1(a) schematically indicates backlight passing through a pair ofcrossed polarizers having two conventional cellulose triacetate (“TAC”)films, both of which have R_(e)=0 nm and R_(th)=−40 nm. FIG. 1(b) showsthe calculated iso-contour plot of light transmission or light leakageaccording to the configuration structure of FIG. 1(a), which has a polarangle from 0° to 80° and an azimuthal angle from 0° to 360°. Thecalculated results show that there exists about 2.2% light leakage at45° along the polarizer transmission axes.

FIG. 2(a) schematically indicates backlight passing through a pair ofcrossed polarizers with one waveplate of Nz=0.5, R_(e)=270 nm, and twozero retardation TAC films (R_(e)=0 nm and R_(th)=0 nm). FIG. 2(b) showsthe calculated iso-contour plot of light transmission or light leakageaccording to the configuration structure of FIG. 2(a), which has a polarangle from 0° to 80° and an azimuthal angle from 0° to 360°. Thecalculated results show that the maximum light leakage is reduced toabout 0.03% at 45° along the polarizer transmission axes, which is agreat improvement compared to the case illustrated in FIG. 1. Thus, awaveplate with Nz=0.5 and R_(e)=270 nm can play a role in reducing lightleakage. Of course, such results are not limited to only waveplateshaving an Nz of 0.5 with an R_(e) of 270. For example, the waveplatecould also be a −A optical film with an R_(e) of −270 nm, among others.If this waveplate is a cellulose based ester, it could replace one ofthe zero retardation films and adhere directly to the PVA layer, whichcould in turn reduce the manufacturing cost. As described below, variousembodiments presented herein concern optical films (e.g., waveplates)having an Nz in the range of from about 0.4 to about 0.9, or of about0.5, comprising cellulose esters.

FIG. 3(a) schematically indicates backlight passing through a pair ofcrossed polarizers with one+A optical film (R_(e)=137.5 nm), one+Coptical film (R_(th)=100 nm) and two zero retardation TAC films (R_(e)=0nm and R_(th)=0 nm). FIG. 3(b) shows the calculated iso-contour plot oflight transmission or light leakage according to the configurationstructure of FIG. 3(a), which has a polar angle from 0° to 80° and anazimuthal angle from 0° to 360°. The calculated results show that themaximum light leakage is reduced to about 0.04% at 45° along thepolarizer transmission axes, which is also a great improvement comparedto the case illustrated in FIG. 1. Therefore, the positive A and Coptical films with indicated retardations played a role in reducing thelight leakage. It needs to be pointed out that the waveplate could alsobe a −A optical film (with, for example, an R_(e) of −137.5 nm) combinedwith a −C optical film (with, for example, an R_(th) of −100 nm). The −Aoptical film could replace the bottom zero retardation film and adheredirectly to the PVA layer, which in turn could reduce manufacturingcosts. Various embodiments presented herein relate to −A optical filmscomprising cellulose esters.

The above simulation examples demonstrate that by adding appropriateoptical films (e.g., waveplates), the light leakage of a pair of crossedpolarizers can be greatly reduced. These optical films also could beused to compensate light leakage of in-plane switching (“IPS”) modeliquid crystal displays, since, though not wishing to bound by theory,it is believed that the light leakage of IPS-LCDs comes primarily fromthe crossed polarizers.

In various embodiments, regioselectively substituted cellulose esterscan be employed in which the aryl-acyl substituent is preferentiallyinstalled at C2 and C3 of the pyranose ring. Regioselectivity can bemeasured by determining the relative degree of substitution (“RDS”) atC6, C3, and C2 in the cellulose ester by carbon 13 NMR spectroscopy(Macromolecules, 1991, 24, 3050-3059). In the case of one type of acylsubstituent or when a second acyl substituent is present in a minoramount (DS<0.2), the RDS can be most easily determined directly byintegration of the ring carbons. When 2 or more acyl substituents arepresent in similar amounts, in addition to determining the ring RDS, itis sometimes necessary to fully substitute the cellulose ester with anadditional substituent in order to independently determine the RDS ofeach substituent by integration of the carbonyl carbons. In conventionalcellulose esters, regioselectivity is generally not observed and the RDSratio of C6/C3, C6/C2, or C3/C2 is generally near 1 or less. In essence,conventional cellulose esters are random copolymers. In contrast, whenadding one or more acylating reagents to cellulose dissolved in anappropriate solvent, the C6 position of cellulose is acylated muchfaster than C2 and C3 positions. Consequently, the C6/C3 and C6/C2ratios are significantly greater than 1, which is characteristic of a6,3- or 6,2-enhanced regioselectively substituted cellulose ester.

Examples of regioselectively substituted cellulose esters and theirmethods for preparation are described in US 2010/0029927, US2010/0267942, and U.S. Pat. No. 8,354,525; the contents of which arehereby incorporated by reference. In general, these applications concernpreparation of cellulose esters by dissolution of cellulose in an ionicliquid, which is then contacted with an acylating reagent. Accordingly,for various embodiments of the present invention, two general methodscan be employed for preparing regioselectively substituted celluloseesters. In one method, regioselectively substituted cellulose esters canbe prepared using a staged addition by first contacting the cellulosesolution with one or more alkyl acylating reagents followed bycontacting the cellulose solution with an aryl-acylating reagent at acontact temperature and contact time sufficient to provide a celluloseester with the desired degree of substitution (“DS”) and degree ofpolymerization (“DP”). In this staged addition, the acyl groupscontaining alkyl groups can be preferentially installed at C6 and theacyl groups containing an aryl group can be preferentially installed atC2 and/or C3. Alternatively, the regioselectively substituted celluloseesters can be prepared by contacting the cellulose solution with one ormore alkyl acylating reagents followed by isolation of the alkyl esterin which the acyl groups containing alkyl groups are preferentiallyinstalled at C6. The alkyl ester can then be dissolved in anyappropriate organic solvent and contacted with an aryl-acylating reagentwhich can preferentially install the acyl groups containing an arylgroup at C2 and/or C3 at a contact temperature and contact timesufficient to provide a cellulose ester with the desired degree ofsubstitution (“DS”) and degree of polymerization (“DP”). The celluloseesters thus prepared generally comprise the following structure:

where R², R³, and R⁶ are hydrogen (with the proviso that R², R³, and R⁶are not hydrogen simultaneously), alkyl-acyl groups, and/or aryl-acylgroups (such as those described above) bound to the cellulose via anester linkage.

The degree of polymerization (“DP”) of the cellulose esters prepared bythese methods can be at least 10. In other embodiments, the DP of thecellulose esters can be at least 50, at least 100, or at least 250. Inother embodiments, the DP of the cellulose esters can be in the range offrom about 5 to about 100, or in the range of from about 10 to about 50.

Acylating reagents suitable for use herein can include, but are notlimited to, alkyl or aryl carboxylic anhydrides, carboxylic acidhalides, and/or carboxylic acid esters containing the above-describedalkyl or aryl groups suitable for use in the acyl substituents of theregioselectively substituted cellulose esters described herein. Examplesof suitable carboxylic anhydrides include, but are not limited to,acetic anhydride, propionic anhydride, butyric anhydride, pivaloylanhydride, benzoic anhydride, and naphthoyl anhydride. Examples ofcarboxylic acid halides include, but are not limited to, acetyl,propionyl, butyryl, pivaloyl, benzoyl, and naphthoyl chlorides orbromides. Examples of carboxylic acid esters include, but are notlimited to, acetyl, propionyl, butyryl, pivaloyl, benzoyl and naphthoylmethyl esters. In one or more embodiments, the acylating reagent can beone or more carboxylic anhydrides selected from the group consisting ofacetic anhydride, propionic anhydride, butyric anhydride, pivaloylanhydride, benzoyl anhydride, and naphthoyl anhydride.

The present application discloses a regioselectively substitutedcellulose ester comprising: (a) a plurality of chromophore-acylsubstituents; and (b) a plurality of pivaloyl substituents, wherein thecellulose ester has a hydroxyl degree of substitution (“DS_(OH)”) in therange of from about 0 to about 0.9, wherein the cellulose ester has apivaloyl degree of substitution (“DS_(Pv)”) in the range of from about0.1 to about 1.2, wherein the cellulose ester has a chromophore-acyldegree of substitution (“DS_(Ch)”) in the range of from about 0.5 toabout 1.6, and wherein the regioselectivity is such that the sum of thechromophore-acyl degree of substitution at C2 and C3 (“C2DS_(Ch)” and“C3DS_(Ch)”) minus the chromophore-acyl degree of substitution at C6(“C6DS_(Ch)”) is between about 0.5 and about 1.6, wherein thechromophore-acyl is chosen from (i) an (C₆₋₂₀)aryl-acyl, wherein thearyl is unsubstituted or substituted by 1-5 R¹; (ii) a heteroaryl-acyl,wherein the heteroaryl is a 5- to 10-membered ring having 1- to4-heteroatoms chosen from N, O, or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹;

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹; or

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from nitro; cyano; (C₁₋₆)alkyl; halo(C₁₋₆)alkyl; halo;(C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl; (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; 5- to10-membered heteroaryl having 1-4 heteroatoms chosen from N, O, or S; or

In one embodiment, the DS_(Pv) is in the range of from about 0.2 toabout 0.8. In one embodiment, the DS_(Pv) is in the range of from about0.3 to about 0.5. In one embodiment, the DS_(Pv) is in the range of fromabout 0.1 to about 0.6. In one embodiment, the DS_(Pv) is in the rangeof from about 0.8 to about 1.2.

In one embodiment, the DS_(Ch) is in the range of from about 0.5 toabout 1.5. In one embodiment, the DS_(Ch) is in the range of from about0.4 to about 0.8. In one embodiment, the DS_(Ch) is in the range of fromabout 0.8 to about 1.6. In one embodiment, the DS_(Ch) is in the rangeof from about 0.7 to about 1.0.

In one embodiment, the DS_(OH) is in the range of from about 0.1 toabout 0.6. In one embodiment, the DS_(OH) is in the range of from about0.1 to about 0.4. In one embodiment, the DS_(OH) is in the range of fromabout 0.4 to about 0.9.

In one embodiment, the DS_(OH) is in the range of from about 0.2 toabout 0.3, the DS_(Pv) is in the range of from about 0.3 to about 0.5,and the DS_(Ch) is in the range of from about 1.0 to about 1.3. In oneclass of this embodiment, the regioselective cellulose ester furthercomprises a plurality of a (C₁₋₆)alkyl-acyl substituent. In one class ofthis embodiment, the C2DS_(Ch) minus C3DS_(Ch) is greater than 0.1. Inone subclass of this class, the regioselectively substituted celluloseester further comprises a plurality of a (C₁₋₆)alkyl-acyl substituent.In one class of this embodiment, the C2DS_(Ch) minus C3DS_(Ch) isgreater than 0.2. In one subclass of this class, the regioselectivelysubstituted cellulose ester further comprises a plurality of a(C₁₋₆)alkyl-acyl substituent.

In one class of this embodiment, the chromophore-acyl is a benzoylunsubstituted or substituted by 1-5 R¹ or a naphthoyl unsubstituted orsubstituted by 1-5 R¹. In one subclass of this class, theregioselectively substituted cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent. In one class of thisembodiment, the chromophore-acyl is a benzoyl unsubstituted orsubstituted by 1-5 R¹. In one subclass of this class, theregioselectively substituted cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent. In one class of thisembodiment, the chromophore-acyl is or a naphthoyl unsubstituted orsubstituted by 1-5 R¹. In one subclass of this class, theregioselectively substituted cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent. In one class of thisembodiment, the chromophore-acyl is naphthoyl. In one class of thisembodiment, the chromophore-acyl is benzoyl. In one subclass of thisclass, the regioselectively substituted cellulose ester furthercomprises a plurality of a (C₁₋₆)alkyl-acyl substituent.

In one embodiment, the DS_(OH) is in the range of from about 0.1 toabout 0.6, the DS_(Pv) is in the range of from about 0.1 to about 0.6,and the DS_(Ch) is in the range of from about 0.5 to about 1.5. In oneclass of this embodiment, the C2DS_(Ch) minus C3DS_(Ch) is greater than0.1. In one subclass of this class, the regioselectively substitutedcellulose ester further comprises a plurality of a (C₁₋₆)alkyl-acylsubstituent. In one class of this embodiment, the C2DS_(Ch) minusC3DS_(Ch) is greater than 0.2. In one subclass of this class, theregioselectively substituted cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent.

In one class of this embodiment, the regioselective cellulose esterfurther comprises a plurality of a (C₁₋₆)alkyl-acyl substituent. In onesubclass of this class, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is in the range of from about0.1 to about 1.4.

In one subclass of this class, the (C₁₋₆)alkyl-acyl substituent ischosen from acetyl, propionyl, butyryl, pentanoyl, or hexanoyl. In onesub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about0.1 to about 1.4. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent is chosen from acetyl or propionyl. In one sub-subclass ofthis subclass, the degree of substitution of the (C₁₋₆)alkyl-acylsubstituent (“DS_(AK)”) is in the range of from about 0.1 to about 1.4.In one subclass of this class, the (C₁₋₆)alkyl-acyl substituentpropionyl. In one sub-subclass of this subclass, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 0.1 to about 1.4. In one subclass of this class, the(C₁₋₆)alkyl-acyl substituent acetyl. In one sub-subclass of thissubclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(AK)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the (C₁₋₆)alkyl-acyl substituent butyryl. In onesub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about0.1 to about 1.4. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent pentanoyl. In one sub-subclass of this subclass, the degreeof substitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is inthe range of from about 0.1 to about 1.4. In one subclass of this class,the (C₁₋₆)alkyl-acyl substituent hexanoyl. In one sub-subclass of thissubclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(AK)”) is in the range of from about 0.1 to about 1.4.

In one embodiment, the DS_(OH) is in the range of from about 0.1 toabout 1.1, the DS_(Pv) is in the range of from about 0.3 to about 0.4,and the DS_(Ch) is in the range of from about 0.3 to about 1.1. In oneclass of this embodiment, the C2DS_(Ch) minus C3DS_(Ch) is greater than0.1. In one subclass of this class, the regioselectively substitutedcellulose ester further comprises a plurality of a (C₁₋₆)alkyl-acylsubstituent. In one class of this embodiment, the C2DS_(Ch) minusC3DS_(Ch) is greater than 0.2. In one subclass of this class, theregioselectively substituted cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent.

In one class of this embodiment, the regioselective cellulose esterfurther comprises a plurality of a (C₁₋₆)alkyl-acyl substituent. In onesubclass of this class, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is in the range of from about0.1 to about 1.3.

In one subclass of this class, the (C₁₋₆)alkyl-acyl substituent ischosen from acetyl, propionyl, butyryl, pentanoyl, or hexanoyl. In onesub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about0.1 to about 1.3. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent is chosen from acetyl or propionyl. In one sub-subclass ofthis subclass, the degree of substitution of the (C₁₋₆)alkyl-acylsubstituent (“DS_(AK)”) is in the range of from about 0.1 to about 1.3.In one subclass of this class, the (C₁₋₆)alkyl-acyl substituentpropionyl. In one sub-subclass of this subclass, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 0.1 to about 1.3. In one subclass of this class, the(C₁₋₆)alkyl-acyl substituent acetyl. In one sub-subclass of thissubclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(AK)”) is in the range of from about 0.1 to about 1.3. In onesubclass of this class, the (C₁₋₆)alkyl-acyl substituent butyryl. In onesub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about0.1 to about 1.3. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent pentanoyl. In one sub-subclass of this subclass, the degreeof substitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is inthe range of from about 0.1 to about 1.3. In one subclass of this class,the (C₁₋₆)alkyl-acyl substituent hexanoyl. In one sub-subclass of thissubclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(AK)”) is in the range of from about 0.1 to about 1.3.

In one embodiment, the DS_(OH) is in the range of from about 0.1 toabout 1.0, the DS_(Pv) is in the range of from about 0.3 to about 0.5,and the DS_(Ch) is in the range of from about 0.8 to about 1.3. In oneclass of this embodiment, the C2DS_(Ch) minus C3DS_(Ch) is greater than0.1. In one subclass of this class, the regioselectively substitutedcellulose ester further comprises a plurality of a (C₁₋₆)alkyl-acylsubstituent. In one class of this embodiment, the C2DS_(Ch) minusC3DS_(Ch) is greater than 0.2. In one subclass of this class, theregioselectively substituted cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent.

In one class of this embodiment, the regioselective cellulose esterfurther comprises a plurality of a (C₁₋₆)alkyl-acyl substituent. In onesubclass of this class, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is in the range of from about0.1 to about 1.4.

In one subclass of this class, the (C₁₋₆)alkyl-acyl substituent ischosen from acetyl, propionyl, butyryl, pentanoyl, or hexanoyl. In onesub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about0.1 to about 1.4. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent is chosen from acetyl or propionyl. In one sub-subclass ofthis subclass, the degree of substitution of the (C₁₋₆)alkyl-acylsubstituent (“DS_(AK)”) is in the range of from about 0.1 to about 1.4.In one subclass of this class, the (C₁₋₆)alkyl-acyl substituentpropionyl. In one sub-subclass of this subclass, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 0.1 to about 1.4. In one subclass of this class, the(C₁₋₆)alkyl-acyl substituent acetyl. In one sub-subclass of thissubclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(AK)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the (C₁₋₆)alkyl-acyl substituent butyryl. In onesub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about0.1 to about 1.4. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent pentanoyl. In one sub-subclass of this subclass, the degreeof substitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is inthe range of from about 0.1 to about 1.4. In one subclass of this class,the (C₁₋₆)alkyl-acyl substituent hexanoyl. In one sub-subclass of thissubclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(AK)”) is in the range of from about 0.1 to about 1.4.

In one embodiment, the regioselectivity is such that the sum of thechromophore-acyl degree of substitution at C2 and C3 (“C2DS_(Ch)” and“C3DS_(Ch)”) minus the chromophore-acyl degree of substitution at C6(“C6DS_(Ch)”) is in the range of from about 0.5 to about 1.6. In oneclass of this embodiment, C2DS_(Ch) minus C3DS_(Ch) is greater than 0.1.In one class of this embodiment, C2DS_(Ch) minus C3DS_(Ch) is greaterthan 0.2. In one class of this embodiment, C2DS_(Ch) minus C3DS_(Ch) isgreater than 0.3. In one class of this embodiment, C2DS_(Ch) minusC3DS_(Ch) is greater than 0.4.

In one embodiment, the regioselectivity is such that the sum of thechromophore-acyl degree of substitution at C2 and C3 (“C2DS_(Ch)” and“C3DS_(Ch)”) minus the chromophore-acyl degree of substitution at C6(“C6DS_(Ch)”) is in the range of from about 0.8 to about 1.6. In oneclass of this embodiment, C2DS_(Ch) minus C3DS_(Ch) is greater than 0.1.In one class of this embodiment, C2DS_(Ch) minus C3DS_(Ch) is greaterthan 0.2. In one class of this embodiment, C2DS_(Ch) minus C3DS_(Ch) isgreater than 0.3. In one class of this embodiment, C2DS_(Ch) minusC3DS_(Ch) is greater than 0.4.

In one embodiment, the regioselectivity is such that the sum of thechromophore-acyl degree of substitution at C2 and C3 (“C2DS_(Ch)” and“C3DS_(Ch)”) minus the chromophore-acyl degree of substitution at C6(“C6DS_(Ch)”) is in the range of from about 0.9 to about 1.6. In oneclass of this embodiment, C2DS_(Ch) minus C3DS_(Ch) is greater than 0.1.In one class of this embodiment, C2DS_(Ch) minus C3DS_(Ch) is greaterthan 0.2. In one class of this embodiment, C2DS_(Ch) minus C3DS_(Ch) isgreater than 0.3. In one class of this embodiment, C2DS_(Ch) minusC3DS_(Ch) is greater than 0.4.

In one embodiment, the chromophore-acyl is an unsubstituted orsubstituted benzoyl or an unsubstituted or substituted naphthoyl,wherein the DS_(OH) is in the range of from about 0.2 to about 0.3,wherein DS_(Pv) is in the range of from about 0.3 to about 0.5, whereinthe DS_(Ch) is in the range of from about 1.0 to about 1.3. In one classof this embodiment, the regioselective cellulose ester further comprisesa plurality of a (C₁₋₆)alkyl-acyl substituent. In one subclass of thisclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(Ak)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the (C₁₋₆)alkyl-acyl substituent is chosen fromacetyl, propionyl, butyryl, pentanoyl, or hexanoyl. In one sub-subclassof this subclass, the degree of substitution of the (C₁₋₆)alkyl-acylsubstituent (“DS_(Ak)”) is in the range of from about 0.1 to about 1.4.In one subclass of this class, the (C₁₋₆)alkyl-acyl substituent ischosen from acetyl or propionyl. In one sub-subclass of this subclass,the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(Ak)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the (C₁₋₆)alkyl-acyl substituent propionyl. Inone sub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is in the range of from about0.1 to about 1.4. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent acetyl. In one sub-subclass of this subclass, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is in therange of from about 0.1 to about 1.4. In one subclass of this class, the(C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclass of thissubclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(Ak)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the (C₁₋₆)alkyl-acyl substituent pentanoyl. Inone sub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is in the range of from about0.1 to about 1.4. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent hexanoyl. In one sub-subclass of this subclass, the degreeof substitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is inthe range of from about 0.1 to about 1.4.

In one embodiment, the chromophore-acyl is an unsubstituted orsubstituted benzoyl or an unsubstituted or substituted naphthoyl,wherein the DS_(OH) is in the range of from about 0.1 to about 0.6,wherein DS_(Pv) is in the range of from about 0.1 to about 0.6, whereinthe DS_(Ar) is in the range of from about 0.5 to about 1.5. In one classof this embodiment, the regioselective cellulose ester further comprisesa plurality of a (C₁₋₆)alkyl-acyl substituent. In one subclass of thisclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(Ak)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the (C₁₋₆)alkyl-acyl substituent is chosen fromacetyl, propionyl, butyryl, pentanoyl, or hexanoyl. In one sub-subclassof this subclass, the degree of substitution of the (C₁₋₆)alkyl-acylsubstituent (“DS_(Ak)”) is in the range of from about 0.1 to about 1.4.In one subclass of this class, the (C₁₋₆)alkyl-acyl substituent ischosen from acetyl or propionyl. In one sub-subclass of this subclass,the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(Ak)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the (C₁₋₆)alkyl-acyl substituent propionyl. Inone sub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is in the range of from about0.1 to about 1.4. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent acetyl. In one sub-subclass of this subclass, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is in therange of from about 0.1 to about 1.4. In one subclass of this class, the(C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclass of thissubclass, the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(Ak)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the (C₁₋₆)alkyl-acyl substituent pentanoyl. Inone sub-subclass of this subclass, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is in the range of from about0.1 to about 1.4. In one subclass of this class, the (C₁₋₆)alkyl-acylsubstituent hexanoyl. In one sub-subclass of this subclass, the degreeof substitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(Ak)”) is inthe range of from about 0.1 to about 1.4.

In one embodiment, the chromophore-acyl has an absorption maximum(λ_(max)) in the range from about 200 nm to about 350 nm. In one classof this embodiment, the regioselectively substituted cellulose esterfurther comprises a plurality of a (C₁₋₆)alkyl-acyl substituent. In onesubclass of this class, the regioselectively substituted cellulose esterfurther comprises a plurality of a (C₁₋₆)alkyl-acyl substituent. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituent ischosen from acetyl, propionyl, butyryl, pentanoyl, or hexanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituent ischosen from acetyl or propionyl. In one sub-subclass of this subclass,the (C₁₋₆)alkyl-acyl substituent propionyl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent acetyl. In one sub-subclassof this subclass, the (C₁₋₆)alkyl-acyl substituent butyryl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituentpentanoyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent hexanoyl.

In one class of this embodiment, the chromophore-acyl has an absorptionmaximum (λ_(max)) in the range from about 230 nm to about 270 nm. In oneclass of this embodiment, the chromophore-acyl has an absorption maximum(λ_(max)) in the range from about 247 nm to about 350 nm.

In one embodiment, chromophore-acyl is (C₆₋₂₀)aryl-acyl, unsubstitutedor substituted by 1-5 R¹. In one class of this embodiment, theregioselectively substituted cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent is chosen from acetyl,propionyl, butyryl, pentanoyl, or hexanoyl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent is chosen from acetyl orpropionyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent propionyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent acetyl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclassof this subclass, the (C₁₋₆)alkyl-acyl substituent pentanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituenthexanoyl.

In one embodiment, the chromophore-acyl is heteroaryl-acyl, wherein theheteroaryl is a 5- to 10-membered ring having 1-4 heteroatoms chosenfrom N, O, or S, and wherein the heteroaryl is unsubstituted orsubstituted by 1-5 R¹. In one class of this embodiment, theregioselective cellulose ester further comprises a plurality of a(C₁₋₆)alkyl-acyl substituent. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl, propionyl, butyryl,pentanoyl, or hexanoyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl or propionyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituentpropionyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent acetyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent pentanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituenthexanoyl.

In one embodiment, the chromophore-acyl is

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹. In one class of this embodiment, theregioselective cellulose ester further comprises a plurality of a(C₁₋₆)alkyl-acyl substituent. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl, propionyl, butyryl,pentanoyl, or hexanoyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl or propionyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituentpropionyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent acetyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent pentanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituenthexanoyl.

In one embodiment, the chromophore-acyl is

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹. In one class of this embodiment,the regioselective cellulose ester further comprises a plurality of a(C₁₋₆)alkyl-acyl substituent. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl, propionyl, butyryl,pentanoyl, or hexanoyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl or propionyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituentpropionyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent acetyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent pentanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituenthexanoyl.

In one embodiment, chromophore-acyl is chosen from a benzoylunsubstituted or substituted by 1-5 R¹, or naphthoyl unsubstituted orsubstituted by 1-5 R¹. In one class of this embodiment, theregioselective cellulose ester further comprises a plurality of a(C₁₋₆)alkyl-acyl substituent. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl, propionyl, butyryl,pentanoyl, or hexanoyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl or propionyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituentpropionyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent acetyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent pentanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituenthexanoyl.

In one embodiment, chromophore-acyl is benzoyl unsubstituted orsubstituted by 1-5 R¹. In one class of this embodiment, theregioselective cellulose ester further comprises a plurality of a(C₁₋₆)alkyl-acyl substituent. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl, propionyl, butyryl,pentanoyl, or hexanoyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent is chosen from acetyl or propionyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituentpropionyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent acetyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent pentanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituenthexanoyl.

In one embodiment, chromophore-acyl is naphthoyl unsubstituted orsubstituted by 1-5 R¹. In one class of this embodiment, the naphthoyl isa 2-naphthoyl. In one class of this embodiment, the naphthoyl is a1-naphthoyl. In one class of this embodiment, the regioselectivecellulose ester further comprises a plurality of a (C₁₋₆)alkyl-acylsubstituent. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent is chosen from acetyl, propionyl, butyryl, pentanoyl, orhexanoyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent is chosen from acetyl or propionyl. In one sub-subclass ofthis subclass, the (C₁₋₆)alkyl-acyl substituent propionyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituent acetyl.In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituentbutyryl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent pentanoyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent hexanoyl.

In one embodiment, the chromophore-acyl is chosen from

wherein * indicates the point of attachment of the chromophore-acylsubstituent to an oxygen of the cellulose ester. In one class of thisembodiment, the regioselective cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent is chosen from acetyl,propionyl, butyryl, pentanoyl, or hexanoyl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent is chosen from acetyl orpropionyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent propionyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent acetyl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclassof this subclass, the (C₁₋₆)alkyl-acyl substituent pentanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituenthexanoyl.

In one embodiment, the chromophore-acyl is chosen from

wherein * indicates the point of attachment of the chromophore-acylsubstituent to an oxygen of the cellulose ester. In one class of thisembodiment, the regioselective cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent is chosen from acetyl,propionyl, butyryl, pentanoyl, or hexanoyl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent is chosen from acetyl orpropionyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent propionyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent acetyl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclassof this subclass, the (C₁₋₆)alkyl-acyl substituent pentanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituenthexanoyl.

In one embodiment, the chromophore-acyl is chosen from

wherein * indicates the point of attachment of the chromophore-acylsubstituent to an oxygen of the cellulose ester. In one class of thisembodiment, the regioselective cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent is chosen from acetyl,propionyl, butyryl, pentanoyl, or hexanoyl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent is chosen from acetyl orpropionyl. In one sub-subclass of this subclass, the (C₁₋₆)alkyl-acylsubstituent propionyl. In one sub-subclass of this subclass, the(C₁₋₆)alkyl-acyl substituent acetyl. In one sub-subclass of thissubclass, the (C₁₋₆)alkyl-acyl substituent butyryl. In one sub-subclassof this subclass, the (C₁₋₆)alkyl-acyl substituent pentanoyl. In onesub-subclass of this subclass, the (C₁₋₆)alkyl-acyl substituenthexanoyl.

In one embodiment, the regioselective cellulose ester further comprisesa plurality of a (C₁₋₆)alkyl-acyl substituent. In one class of thisembodiment, the degree of substitution of the (C₁₋₆)alkyl-acylsubstituent (“DS_(AK)”) is in the range of from about 0.1 to about 1.4.In one class of this embodiment, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about1.1 to about 1.4. In one class of this embodiment, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 0.1 to about 1.1.

In one class of this embodiment, the (C₁₋₆)alkyl-acyl substituent ischosen from acetyl, propionyl, butyryl, pentanoyl, or hexanoyl. In onesubclass of this class, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about0.1 to about 1.4. In one subclass of this class, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 1.1 to about 1.4. In one subclass of this class, thedegree of substitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”)is in the range of from about 0.1 to about 1.1. In one class of thisembodiment, the (C₁₋₆)alkyl-acyl substituent is chosen from acetyl orpropionyl. In one subclass of this class, the degree of substitution ofthe (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of fromabout 0.1 to about 1.4. In one subclass of this class, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 1.1 to about 1.4. In one subclass of this class, thedegree of substitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”)is in the range of from about 0.1 to about 1.1. In one class of thisembodiment, the (C₁₋₆)alkyl-acyl substituent propionyl. In one subclassof this class, the degree of substitution of the (C₁₋₆)alkyl-acylsubstituent (“DS_(AK)”) is in the range of from about 0.1 to about 1.4.In one subclass of this class, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about1.1 to about 1.4. In one subclass of this class, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 0.1 to about 1.1. In one class of this embodiment,the (C₁₋₆)alkyl-acyl substituent acetyl. In one subclass of this class,the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(AK)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about1.1 to about 1.4. In one subclass of this class, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 0.1 to about 1.1. In one class of this embodiment,the (C₁₋₆)alkyl-acyl substituent butyryl. In one subclass of this class,the degree of substitution of the (C₁₋₆)alkyl-acyl substituent(“DS_(AK)”) is in the range of from about 0.1 to about 1.4. In onesubclass of this class, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about1.1 to about 1.4. In one subclass of this class, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 0.1 to about 1.1. In one class of this embodiment,the (C₁₋₆)alkyl-acyl substituent pentanoyl. In one class of thisembodiment, the (C₁₋₆)alkyl-acyl substituent hexanoyl. In one subclassof this class, the degree of substitution of the (C₁₋₆)alkyl-acylsubstituent (“DS_(AK)”) is in the range of from about 0.1 to about 1.4.In one subclass of this class, the degree of substitution of the(C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in the range of from about1.1 to about 1.4. In one subclass of this class, the degree ofsubstitution of the (C₁₋₆)alkyl-acyl substituent (“DS_(AK)”) is in therange of from about 0.1 to about 1.1.

Films

The present application also discloses a film comprising aregioselectively substituted cellulose ester comprising: (a) a pluralityof chromophore-acyl substituents; and (b) a plurality of pivaloylsubstituents, wherein the cellulose ester has a hydroxyl degree ofsubstitution (“DS_(OH)”) in the range of from about 0 to about 0.9,wherein the cellulose ester has a pivaloyl degree of substitution(“DS_(Pv)”) in the range of from about 0.1 to about 1.2, wherein thecellulose ester has a chromophore-acyl degree of substitution(“DS_(Ch)”) in the range of from about 0.5 to about 1.6, and wherein theregioselectivity is such that the sum of the chromophore-acyl degree ofsubstitution at C2 and C3 (“C2DS_(Ch)” and “C3DS_(Ch)”) minus thechromophore-acyl degree of substitution at C6 (“C6DS_(Ch)”) is betweenabout 0.5 and about 1.6, wherein the chromophore-acyl is chosen from (i)an (C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or substituted by1-5 R¹; (ii) a heteroaryl-acyl, wherein the heteroaryl is a 5- to10-membered ring having 1- to 4-heteroatoms chosen from N, O, or S, andwherein the heteroaryl is unsubstituted or substituted by 1-5 R¹;

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹; or

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from nitro, cyano, (C₁₋₆)alkyl; halo(C₁₋₆)alkyl;(C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl; (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo; 5-to 10-membered heteroaryl having 1-4 heteroatoms chosen from N, O, or S;or

In one embodiment of this film, the chromophore-acyl is an(C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or substituted by1-5 R¹. In one class of this embodiment, the regioselectivelysubstituted cellulose ester further comprises a plurality of a(C₁₋₆)alkyl-acyl substituent.

In one class of this embodiment, the (C₆₋₂₀)aryl-acyl is benzoyl ornaphthoyl. In one subclass of this class, the regioselectivelysubstituted cellulose ester further comprises a plurality of a(C₁₋₆)alkyl-acyl substituent.

In one class of this embodiment, the (C₆₋₂₀)aryl-acyl is benzoyl.

In one class of this embodiment, the (C₆₋₂₀)aryl-acyl is naphthoyl. Inone subclass of this class, the naphthoyl is 2-naphthoyl. In onesubclass of this class, the naphthoyl is 1-naphthoyl.

In one embodiment of this film, the chromophore-acyl is aheteroaryl-acyl, wherein the heteroaryl is a 5- to 10-membered ringhaving 1- to 4-heteroatoms chosen from N, O, or S, and wherein theheteroaryl is unsubstituted or substituted by 1-5 R¹. In one class ofthis embodiment, the regioselectively substituted cellulose esterfurther comprises a plurality of a (C₁₋₆)alkyl-acyl substituent.

In one embodiment of this film, the chromophore-acyl is

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹. In one class of this embodiment, theregioselectively substituted cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent.

In one embodiment of this film, the chromophore-acyl is

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹. In one class of this embodiment,the regioselectively substituted cellulose ester further comprises aplurality of a (C₁₋₆)alkyl-acyl substituent.

In one embodiment of this film, the chromophore-acyl is chosen from

wherein * indicates the point of attachment of the chromophore-acylsubstituent to an oxygen of the cellulose ester. In one class of thisembodiment, the regioselectively substituted cellulose ester furthercomprises a plurality of a (C₁₋₆)alkyl-acyl substituent.

In one embodiment of this film, the chromophore-acyl is chosen from

wherein * indicates the point of attachment of the chromophore-acylsubstituent to an oxygen of the cellulose ester. In one class of thisembodiment, the regioselectively substituted cellulose ester furthercomprises a plurality of a (C₁₋₆)alkyl-acyl substituent.

In one embodiment, the chromophore-acyl has an absorption maximum(λ_(max)) in the range of from about 200 nm to about 350 nm. In oneclass of this embodiment, the regioselectively substituted celluloseester further comprises a plurality of a (C₁₋₆)alkyl-acyl substituent.

In one embodiment of this film, chromophore-acyl is a naphthoylunsubstituted or substituted by 1-5 R¹, the DS_(OH) is in the range offrom about 0.2 to about 0.3, the DS_(Pv) is in the range of from about0.3 to about 0.5, the DS_(Ch) is in the range of from about 1.1 to about1.3. In one class of this embodiment, the film has a thickness in therange of from about 0.5 μm to about 5 μm. In one class of thisembodiment, the film has a thickness in the range of from about 5 μm toabout 20 μm.

In one embodiment of this film, the film is 45 degree, a uniaxial or abiaxial stretched optical film. In one class of this embodiment, thefilm is a 45 degree stretched optical film. In one class of thisembodiment, the film is a uniaxial stretched optical film. In one classof this embodiment, the film is a biaxial stretched optical film.

In another embodiment of this film, the film is diagonally 45°stretched, which will increase the circular polarizer manufacture outputthrough roll to roll lamination process for 3D display, OLED and otherapplications.

In one embodiment is a polarizer plate comprising the film. In oneembodiment is a circular polarizer comprising the film.

In one embodiment is a multilayer film comprising the film. In one classof this embodiment, the multilayer film is an A plate film. In one classof this embodiment, the multilayer film has a thickness in the range offrom about 20 μm to about 140 μm.

In one class of this embodiment, the multilayer film is 45 degree,uniaxially, or biaxially stretched. In one class of this embodiment, themultilayer film is 45 degree stretched. In one class of this embodiment,the multilayer film is uniaxially stretched. In one class of thisembodiment, the multilayer film is biaxially stretched. In one class ofthis embodiment, the multilayer film comprises at least two filmsprepared by lamination, coating, or co-casting. In one subclass of thisembodiment, the multilayer film is prepared by lamination, coating, orco-casting. In one sub-subclass of this subclass, the multilayer film isprepared by lamination. In one sub-subclass of this subclass, themultilayer film is prepared by coating. In one sub-subclass of thissubclass, the multilayer film is prepared by co-casting.

In one embodiment of this film, the film has a transmission b* valuethat is less than 0.8. In one embodiment of this film the film has atransmission b* value that is less than 0.7. In one embodiment of thisfilm, the film has a transmission b* value that is less than 0.6. In oneembodiment of this film, the film has a b* of less than 0.5. In oneembodiment of this film, the film has a transmission b* value that isless than 0.4. In one embodiment of this film, the film has atransmission b* value that is less than 0.3.

In one embodiment of this film, the film has a birefringence (“Δn”) isin the range of from about 0.001 to about 0.020 as measured at awavelength of 589 nm. In one class of this embodiment, the film has athickness about 1 μm to about 20 μm. In one embodiment, the film has abirefringence (“Δn”) is in the range of from about 0.006 to about 0.020as measured at a wavelength of 589 nm. In one class of this embodiment,the film has a thickness about 1 μm to about 20 μm. In one embodiment ofthis film, the film has a Δn is in the range of from about 0.008 toabout 0.020 as measured at a wavelength of 589 nm. In one class of thisembodiment, the film has a thickness about 1 μm to about 20 μm. In oneembodiment of this film, the film has a Δn is in the range of from about0.009 to about 0.020 as measured at a wavelength of 589 nm. In one classof this embodiment, the film has a thickness 5 μm to about 20 μm. In oneembodiment, the film has a Δn is in the range of from about 0.01 toabout 0.020 as measured at a wavelength of 589 nm. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm.

In one embodiment of this film, the film has a percent haze of less thanabout 4.0. In one class of this embodiment, the film has a thickness 1μm to about 20 μm. In one embodiment of this film, the film has apercent haze of less than about 3.0. In one class of this embodiment,the film has a thickness 1 μm to about 20 μm. In one embodiment of thisfilm, the film has a percent haze of less than about 2.0. In one classof this embodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment, the film has a percent haze of less than about 1.0. In oneclass of this embodiment, the film has a thickness 1 μm to about 20 μm.In one embodiment, the film has a percent haze of less than about 0.9.In one class of this embodiment, the film has a thickness 1 μm to about20 μm. In one embodiment, the film has a percent haze of less than about0.8. In one class of this embodiment, the film has a thickness 1 μm toabout 20 μm. In one embodiment, the film has a percent haze of less thanabout 0.7. In one class of this embodiment, the film has a thickness 1μm to about 20 μm. In one embodiment, the film has a percent haze ofless than about 0.6. In one class of this embodiment, the film has athickness 1 μm to about 20 μm. In one embodiment, the film has a percenthaze of less than about 0.5. In one class of this embodiment, the filmhas a thickness 1 μm to about 20 μm. In one embodiment, the film has apercent haze of less than 0.4. In one class of this embodiment, the filmhas a thickness 1 μm to about 20 μm. In one embodiment, the film has apercent haze of less than about 0.3. In one class of this embodiment,the film has a thickness 1 μm to about 20 μm. In one embodiment, thefilm has a percent haze of less than about 0.2. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm.

The film thickness may depend upon the film thickness before stretchingand upon the stretching conditions. After stretching, the film thicknesscan be from about 1 μm to about 500 μm, from about 5 μm to about 200 μm,from about 10 μm to about 120 μm, from about 20 μm to about 100 μm, fromabout 30 μm to about 80 μm, from about 40 μm to about 80 μm, or about 20μm to about 140 μm. In one embodiment of this film, the thickness of thefilm after stretching is in the range of from about 0.5 μm to about 20μm.

Before stretching the film can have an average thickness ranging fromabout 1 μm to about 500 μm, from about 5 μm to about 200 μm, from about10 μm to about 120 μm, from about 20 μm to about 100 μm, from about 30μm to about 80 μm, or from about 40 μm to about 80 μm. In one embodimentof this film, the thickness of the film before stretching is in therange of from about 0.5 μm to about 20 μm.

In one embodiment of this film, the film is a +C film, −C film, or a +Afilm. In one class of this embodiment, the film has a thickness in therange of 0.5 μm to about 20 μm. In one class of this embodiment, thefilm has a thickness in the range of 20 μm to about 140 μm.

In one class of this embodiment, the film is a +C film. In one subclassof this class, the film has a thickness in the range of 0.5 μm to about20 μm. In one subclass of this class, the film has a thickness in therange of 20 μm to about 140 μm. In one class of this embodiment, thefilm is a −C film. In one subclass of this class, the film has athickness in the range of 0.5 μm to about 20 μm. In one subclass of thisclass, the film has a thickness in the range of 20 μm to about 140 μm.In one class of this embodiment, the film is a +A film. In one subclassof this class, the film has a thickness in the range of 0.5 μm to about20 μm. In one subclass of this class, the film has a thickness in therange of 20 μm to about 140 μm. In one class of this embodiment, thefilm is a −A film. In one subclass of this class, the film has athickness in the range of 0.5 μm to about 20 μm. In one subclass of thisclass, the film has a thickness in the range of 20 μm to about 140 μm.

In one embodiment of this film, the film has an out-of-plane retardation(“R_(th)”) in the range of from about 44 nm to about 244 nm as measuredat a wavelength of about 589 nm at a thickness in the range of fromabout 14 μm to about 19 μm. In one embodiment, the film has a R_(th) inthe range of from about 80 nm to about 120 nm as measured at awavelength of about 589 nm at a thickness in the range of from about 8μm to about 16 μm.

In one embodiment of this film, the film has an out-of-plane retardation(“R_(th)”) in the range of from about −100 nm to about 100 nm, asmeasured at a wavelength of about 589 nm at a thickness in the range offrom about 2 μm to about 15 μm. In one class of this embodiment, thefilm is unstretched. In one embodiment of this film, the film has anout-of-plane retardation (“R_(th)”) is in the range of from about −50 nmto about 50 nm as measured at a wavelength of about 589 nm at athickness in the range of from about 2 μm to about 17 μm. In one classof this embodiment, the film is unstretched.

In one embodiment of this film, the film has an in-plane retardation(“R_(e)”) is in the range of from about −0.5 nm to about 5 nm asmeasured at a wavelength of about 589 nm at a thickness in the range offrom about 2 μm to about 17 μm. In one class of this embodiment, thefilm is unstretched.

In one embodiment, the film has a positive in-plane retardation thatsatisfies the relations of −0.5<R_(e)(450)/R_(e)(550)<5 and−1.6<R_(e)(650)/R_(e)(550)<1.5, wherein R_(e)(450), R_(e)(550), andR_(e)(650) are in-plane retardations at the light wavelengths of 450 nm,550 nm, and 650 nm, respectively.

In one embodiment, the film has a positive out-of-plane retardation thatsatisfies the relations of 0.5<R_(th)(450)/R_(th)(550)<2.5 and0.4<R_(th)(650)/R_(th)(550)<1.3, wherein R_(th)(450), R_(th)(550), andR_(th)(650) are in-plane retardations at the light wavelengths of 450nm, 550 nm, and 650 nm, respectively.

The films can comprise one or more of the above-describedregioselectively substituted cellulose esters. In one embodiment, thefilm comprises a regioselectively substituted cellulose ester having aDS_(Pv) in the range of from about 0.1 to about 1.2.

In one embodiment of this film, the chromophore-acyl is a benzoylunsubstituted or substituted by 1-5 R¹; or a naphthoyl unsubstituted orsubstituted by 1-5 R¹, wherein the DS_(OH) is in the range of from about0.2 to about 0.3, wherein DS_(Pv) is in the range of from about 0.3 toabout 0.5, wherein the DS_(Ar) is in the range of from about 1.0 toabout 1.3.

In one embodiment, the DS_(Pv) is in the range of from about 0.2 toabout 0.8. In one embodiment, the DS_(Pv) is in the range of from about0.3 to about 0.5. In one embodiment, the DS_(Pv) is in the range of fromabout 0.1 to about 0.6. In one embodiment, the DS_(Pv) is in the rangeof from about 0.8 to about 1.2.

In one embodiment, the DS_(Ch) is in the range of from about 0.5 toabout 1.5. In one embodiment, the DS_(Ch) is in the range of from about0.4 to about 0.8. In one embodiment, the DS_(Ch) is in the range of fromabout 0.8 to about 1.6. In one embodiment, the DS_(Ch) is in the rangeof from about 0.7 to about 1.0.

In one embodiment, the DS_(OH) is in the range of from about 0.1 toabout 0.6. In one embodiment, the DS_(OH) is in the range of from about0.1 to about 0.4. In one embodiment, the DS_(OH) is in the range of fromabout 0.4 to about 0.9.

In one embodiment, the DS_(OH) is in the range of from about 0.1 toabout 0.6, the DS_(Pv) is in the range of from about 0.1 to about 0.6,and the DS_(Ch) is in the range of from about 0.5 to about 1.5. In oneembodiment, the DS_(OH) is in the range of from about 0.1 to about 1.1,the DS_(Pv) is in the range of from about 0.3 to about 0.4, and theDS_(Ch) is in the range of from about 0.3 to about 1.1. In oneembodiment, the DS_(OH) is in the range of from about 0.1 to about 1.0,the DS_(Pv) is in the range of from about 0.3 to about 0.5, and theDS_(Ch) is in the range of from about 0.8 to about 1.3.

In one embodiment, the regioselectivity is such that the sum of thechromophore-acyl degree of substitution at C2 and C3 (“C2DS_(Ch)” and“C3DS_(Ch)”) minus the chromophore-acyl degree of substitution at C6(“C6DS_(Ch)”) is in the range of from about 0.5 to about 1.6. In oneembodiment, the regioselectivity is such that the sum of thechromophore-acyl degree of substitution at C2 and C3 (“C2DS_(Ch)” and“C3DS_(Ch)”) minus the chromophore-acyl degree of substitution at C6(“C6DS_(Ch)”) is in the range of from about 0.8 to about 1.6. In oneembodiment, the regioselectivity is such that the sum of thechromophore-acyl degree of substitution at C2 and C3 (“C2DS_(Ch)” and“C3DS_(Ch)”) minus the chromophore-acyl degree of substitution at C6(“C6DS_(Ch)”) is in the range of from about 0.9 to about 1.6.

The films can be formed into multilayer films. The multilayer films canbe made by solvent co-casting, melt co-extrusion, lamination, or acoating process. These procedures are generally known in the art.Examples of solvent co-casting, melt co-extrusion, lamination, andcoating methods to form multilayer structures are found in US2009/0050842, US 2009/0054638, and US 2009/0096962.

Further examples of solvent co-casting, melt co-extrusion, lamination,and coating methods to form a multilayer structure are found in U.S.Pat. Nos. 4,592,885; 7,172,713; US 2005/0133953; and US 2010/0055356,the contents of which are hereby incorporated by reference in theirentirety.

The multilayer film may be configured in an A-B structure or an A-B-Astructure (FIGS. 4(a) and 4(b), respectively). In one embodiment, layerA can be made from the cellulose esters of disclosed herein, and layer Bcan be made from the cellulose esters disclosed herein, anothercellulose ester, a polycarbonate, a polyester, a polyimide, acycloolefin polymer, or a cycloolefin copolymer. Layer B can also bemade from a combination of the aforementioned polymers. Examples ofanother cellulose ester include a cellulose acetate butyrate, acellulose acetate, a cellulose acetate propionate, a cellulosepropionate, and a cellulose butyrate. In the case of a bi-layerstructure, the layers are made using different cellulose esters. For thetri-layer structure, the top and bottom layers are made using the samecellulose ester and the middle layer is made using a different celluloseester. Other configurations are possible such as A-X-B where X is anadhesive or tie layer, and B-A-B. The thickness of each layer can be thesame or different. By varying the thickness of each layer, the desiredoptical retardation and reversed optical dispersion can be obtained. Thethickness of layer A before after stretching can range from about 1 μmto about 20 μm, and the thickness of layer B after stretching can rangefrom about 19 μm to about 120 μm.

To obtain certain in-plane retardation (R_(e)) values, the multilayerfilm may be stretched. By adjusting the stretch conditions such asstretch temperature, stretch ratio, stretch type (e.g., 45 degree,uniaxial or biaxial), pre-heat time and temperature, and post-stretchannealing time and temperature; the desired R_(e), R_(th), and reverseoptical dispersion can be achieved. The stretching temperature can rangefrom 130° C. to 200° C. The stretch ratio can range from 1.0 to 1.4 inthe machine direction (MD) and can range from 1.1 to 2.0 in thetransverse direction (TD). The pre-heat time can range from 10 to 300seconds, and the pre-heat temperature can be the same as the stretchtemperature. The post-annealing time can range from 0 to 300 seconds,and the post-annealing temperature can range from 10° C. to 40° C. belowthe stretching temperature.

It is known in the art of optical compensation film that the phaseretardation of light varies according to wavelength, causing colorshift. This wavelength dependence (or dispersion) characteristic of thecompensation film may be taken into account when designing an opticaldevice so that color shift is minimized. Wavelength dispersion curvesare defined as “normal”, “flat” or “reversed” with respect to thecompensation film having positive, none or negative retardance (orretardation). A compensation film with positive retardance (positiveA-plate or C-plate) may have a normal dispersion curve in which thevalue of phase retardation is increasingly positive toward shorterwavelengths or a reversed dispersion curve in which the value of phaseretardation is decreasingly positive toward shorter wavelengths. Acompensation film with negative retardance (negative A-plate or C-plate)may have a normal dispersion curve in which the value of phaseretardation is increasingly negative toward shorter wavelengths or areversed dispersion curve in which the value of phase retardation isdecreasingly negative toward shorter wavelengths. Exemplary shapes ofthese curves are depicted in FIG. 1.

Wave plates are customarily named as follows in accordance with theirrefractive index profiles:positive A-plate: n _(x) >n _(y) =n _(z); negative A-plate: n _(x) <n_(y) =n _(z)positive C-plate: n _(x) =n _(y) <n _(z); negative C-plate: n _(x) =n_(y) >n _(z)wherein, n_(x) and n_(y) represent in-plane refractive indices, andn_(z) the thickness refractive index.

The above wave plates are uniaxial birefringent plates. A wave plate canalso be biaxial birefringent, where n_(x), n_(y), and n_(z) are all notequal; it is customarily named as biaxial film.

An A-plate having in-plane retardation (R_(e)) equal to a quarter of thewavelength (λ/4) is named quarter wave plate (QWP). An ideal achromaticQWP has the in-plane retardation of λ/4 at every wavelength. In order toachieve this, the wavelength dispersion of the QWP has to be reversedand satisfies the following equations:R _(e)(450)/R _(e)(550)=0.818 and R _(e)(650)/R _(e)(550)=1.182,wherein R_(e)(450), R_(e)(550), and R_(e)(650) are in-plane retardationsat the light wavelengths of 450 nm, 550 nm, and 650 nm respectively.

An achromatic (or broadband) wave plate is highly desirable since it candirect the light in the same manner at each wavelength to yield theoptimal viewing quality. A common wave plate, however, exhibits a normaldispersion curve, which is not suitable for broadband wave plateapplication. Thus, there exists a need for a wave plate having reversedwavelength dispersion characteristics with respect to in-plane and outof plane retardations.

A-plates are commonly used in liquid crystal displays (LCDs) ascompensation films to improve the viewing angles. They can also be usedin an OLED (organic light emitting diode) display device. For example, aQWP is being used with a linear polarizer to provide a circularpolarizer in an OLED device to reduce the ambient light reflected byOLED for improved viewing quality. These applications typically utilizethe in-plane retardation provided by the A-plate for in-planephase-shift compensation. For example, A-plate combining with C-plate isparticularly useful in reducing light leakage of the crossed polarizersat oblique viewing angles.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film is an A-plate film. In one class of this embodiment, themultilayer film has a thickness in the range of 20 μm to about 140 μm.In one subclass of this class, the film has a thickness in the range offrom about 1 μm to about 20 μm. In one subclass of this class, themultilayer film is 45 degree, uniaxially, or biaxially stretched. In onesubclass of this class, the multilayer film is 45 degree stretched. Inone subclass of this embodiment, the multilayer film is uniaxiallystretched.

In one class of this embodiment, the A-plate film is a negative A-platefilm. In one subclass of this class, the multilayer film has a thicknessin the range of 20 μm to about 140 μm. In one sub-subclass of thissubclass, the multilayer film is 45 degree, uniaxially, or biaxiallystretched. In one sub-sub-subclass of this sub-subclass, the film has athickness in the range of from about 1 μm to about 20 μm. In onesub-subclass of this subclass, the multilayer film is 45 degreestretched. In one sub-subclass of this subclass, the multilayer film isuniaxially stretched.

In one class of this embodiment, the A-plate film is a positive A-platefilm. In one subclass of this class, the multilayer film has a thicknessin the range of 20 μm to about 140 μm. In one sub-subclass of thissubclass, the multilayer film is 45 degree, uniaxially, or biaxiallystretched. In one sub-sub-subclass of this sub-subclass, the film has athickness in the range of from about 1 μm to about 20 μm. In onesub-subclass of this subclass, the multilayer film is 45 degreestretched. In one sub-subclass of this subclass, the multilayer film isuniaxially stretched.

In one embodiment, the multilayer film further comprises another filmcomprising another cellulose ester, a polycarbonate, a polyester, apolyimide, a cycloolefin polymer, a cycloolefin copolymer, orcombinations thereof. In one class of this embodiment, the celluloseester is a cellulose acetate butyrate, a cellulose acetate, a celluloseacetate propionate, a cellulose propionate, a cellulose butyrate, orcombinations thereof. In one class of this embodiment, the celluloseester is a cellulose acetate butyrate. In one class of this embodiment,the cellulose ester is a cellulose acetate. In one class of thisembodiment, the cellulose ester is a cellulose acetate propionate. Inone class of this embodiment, the cellulose ester is, a cellulosepropionate. In one class of this embodiment, the cellulose ester is acellulose butyrate.

In one class of this embodiment, the another film comprises apolycarbonate. In one class of this embodiment, the another filmcomprises a polyester. In one class of this embodiment, the another filmcomprises a polyimide. In one class of this embodiment, the another filmcomprises a cycloolefin polymer. In one class of this embodiment, theanother film comprises a cycloolefin copolymer.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film has an out-of-plane retardation (“R_(th)”) is in therange of from about −300 nm to about 0 nm, as measured at 589 nm at athickness in the range of from about 20 μm to about 140 μm, wherein themultilayer film stretched. In one class of this embodiment, themultilayer film is uniaxially, biaxially, or 45 degree stretched. In oneclass of this embodiment, the multilayer film has a thickness in therange of from about 20 μm to about 140 μm. In one subclass of thisclass, the film has a thickness in the range of from about 1 μm to about20 μm. In one subclass of this class, the multilayer film is uniaxially,biaxially, or 45 degree stretched.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film has an out-of-plane retardation (“R_(th)”) measured at589 nm is in the range of from about −200 nm to about −50 nm, asmeasured at 589 nm at a thickness in the range of from about 20 μm toabout 140 μm, wherein the multilayer film is a stretched. In one classof this embodiment, the multilayer film is uniaxially, biaxially, or 45degree stretched. In one class of this embodiment, the multilayer filmhas a thickness in the range of from about 20 μm to about 140 μm. In onesubclass of this class, the film has a thickness in the range of fromabout 1 μm to about 20 μm. In one subclass of this class, the multilayerfilm is uniaxially, biaxially, or 45 degree stretched.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film has in-plane retardation (R_(e)) in the range of about40 to about 160 nm, in the range of about 50 to 150 nm, in the range ofabout 100 to 150 nm or in the range of about 110 to 150 nm andout-of-plane retardation (R_(th)) of about 0 to about −200 nm, in therange of about 0 to −150 nm or in the range of about −30 to −100 nm atthe wavelength (λ) 550 nm. In one class of this embodiment, themultilayer film is uniaxially, biaxially, or 45 degree stretched. In oneclass of this embodiment, the multilayer film has a thickness in therange of from about 20 μm to about 140 μm. In one subclass of thisclass, the film has a thickness in the range of from about 1 μm to about20 μm. In one subclass of this class, the multilayer film is uniaxially,biaxially, or 45 degree stretched.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film has a positive in-plane retardation that satisfies therelations of 0.7<R_(e)(450)/R_(e)(550)<1 and1<R_(e)(650)/R_(e)(550)<1.25, wherein R_(e)(450), R_(e)(550), andR_(e)(650) are in-plane retardations at the light wavelengths of 450 nm,550 nm, and 650 nm, respectively. In one class of this embodiment, themultilayer film is uniaxially, biaxially, or 45 degree stretched. In oneclass of this embodiment, the multilayer film has a thickness in therange of from about 20 μm to about 140 μm. In one subclass of thisclass, the film has a thickness in the range of from about 1 μm to about20 μm. In one subclass of this class, the multilayer film is uniaxially,biaxially, or 45 degree stretched.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film has an in-plane retardation (R_(e)) of about 50 to about160 nm at the light wavelength of 550 nm. In one embodiment of thisfilm, the film has an out-of-plane retardation (R_(th)) of about −200 nmto about 0 nm at the light wavelength of 550 nm. In one class of thisembodiment, the multilayer film is uniaxially, biaxially, or 45 degreestretched. In one class of this embodiment, the multilayer film has athickness in the range of from about 20 μm to about 140 μm. In onesubclass of this class, the film has a thickness in the range of fromabout 1 μm to about 20 μm. In one subclass of this class, the multilayerfilm is uniaxially, biaxially, or 45 degree stretched.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film has an in-plane retardation (R_(e)) of about 50 to about160 nm and out-of-plane retardation (R_(th)) of about −200 to about 20nm as measured at the wavelength of 550 nm. In one class of thisembodiment, the multilayer film is uniaxially, biaxially, or 45 degreestretched. In one class of this embodiment, the multilayer film has athickness in the range of from about 20 μm to about 140 μm. In onesubclass of this class, the film has a thickness in the range of fromabout 1 μm to about 20 μm. In one subclass of this class, the multilayerfilm is uniaxially, biaxially, or 45 degree stretched.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film has an in-plane retardation (R_(e)) of about 50 to about160 nm and an out-of-plane retardation (R_(th)) of about −200 to about20 nm at the wavelength (λ) 550 nm, and a positive in-plane retardation(R_(e)) that satisfies the relations of 0.7<R_(e)(450)/R_(e)(550)<1 and1<R_(e)(650)/R_(e)(550)<1.25, wherein R_(e)(450), R_(e)(550), andR_(e)(650) are in-plane retardations measured at the light wavelengthsof 450 nm, 550 nm, and 650 nm respectively. In one class of thisembodiment, the multilayer film is uniaxially, biaxially, or 45 degreestretched. In one class of this embodiment, the multilayer film has athickness in the range of from about 20 μm to about 140 μm. In onesubclass of this class, the film has a thickness in the range of fromabout 1 μm to about 20 μm. In one subclass of this class, the multilayerfilm is uniaxially, biaxially, or 45 degree stretched.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film has an in-plane retardation (R_(e)) of about 50 to about160 nm and an out-of-plane retardation (R_(th)) of about −20 to about−200 nm at the wavelength (λ) 550 nm, and a positive in-planeretardation (R_(e)) that satisfies the relations of0.75<R_(e)(450)/R_(e)(550)<0.9 and 1.05<R_(e)(650)/R_(e)(550)<1.2,wherein R_(e)(450), R_(e)(550), and R_(e)(650) are in-plane retardationsmeasured at the light wavelengths of 450 nm, 550 nm, and 650 nmrespectively. In one class of this embodiment, the multilayer film isuniaxially, biaxially, or 45 degree stretched. In one class of thisembodiment, the multilayer film has a thickness in the range of fromabout 20 μm to about 140 μm. In one subclass of this class, themultilayer film is uniaxially, biaxially, or 45 degree stretched.

In one embodiment is a multilayer film comprising the film, wherein themultilayer film is 45 degree, uniaxially, or biaxially stretched. In oneclass of this embodiment, the multilayer film has a thickness in therange of from about 20 μm to about 140 μm. In one subclass of thisclass, the multilayer film has a positive in-plane retardation thatsatisfies the relations of 0.7<R_(e)(450)/R_(e)(550)<1 and1<R_(e)(650)/R_(e)(550)<1.25, wherein R_(e)(450), R_(e)(550), andR_(e)(650) are in-plane retardations at the light wavelengths of 450 nm,550 nm, and 650 nm, respectively. In one sub-subclass of this subclass,the film has a thickness in the range of from about 1 μm to about 20 μm.In one sub-subclass of this subclass, the multilayer film is uniaxiallystretched. In one sub-subclass of this subclass, the multilayer film isbiaxially stretched. In one sub-subclass of this subclass, themultilayer film is 45 degree stretched.

In one subclass of this class, the multilayer film has an in-planeretardation (R_(e)) in the range of about 40 to about 160 nm, in therange of about 50 to 150 nm, in the range of about 100 to 150 nm or inthe range of about 110 to 150 nm and out-of-plane retardation (R_(th))of about 0 to about −200 nm, in the range of about 0 to −150 nm or inthe range of about −30 to −100 nm at the wavelength (λ) 550 nm. In onesub-subclass of this subclass, the film has a thickness in the range offrom about 1 μm to about 20 μm. In one sub-subclass of this subclass,the multilayer film is uniaxially stretched. In one sub-subclass of thissubclass, the multilayer film is biaxially stretched. In onesub-subclass of this subclass, the multilayer film is 45 degreestretched.

In one subclass of this class, the multilayer film has an in-planeretardation (R_(e)) of about 50 to about 160 nm at the light wavelengthof 550 nm. In one sub-subclass of this subclass, the film has athickness in the range of from about 1 μm to about 20 μm. In onesub-subclass of this subclass, the multilayer film is uniaxiallystretched. In one sub-subclass of this subclass, the multilayer film isbiaxially stretched. In one sub-subclass of this subclass, themultilayer film is 45 degree stretched.

In one subclass of this class, the multilayer film has an out-of-planeretardation (R_(th)) of about −200 nm to about 0 nm at the lightwavelength of 550 nm. In one sub-subclass of this subclass, the film hasa thickness in the range of from about 1 μm to about 20 μm. In onesub-subclass of this subclass, the multilayer film is uniaxiallystretched. In one sub-subclass of this subclass, the multilayer film isbiaxially stretched. In one sub-subclass of this subclass, themultilayer film is 45 degree stretched.

In one subclass of this class, the multilayer film has an in-planeretardation (R_(e)) of about 50 to about 160 nm and out-of-planeretardation (R_(th)) of about −200 to about 20 nm as measured at thewavelength of 550 nm. In one sub-subclass of this subclass, the film hasa thickness in the range of from about 1 μm to about 20 μm. In onesub-subclass of this subclass, the multilayer film is uniaxiallystretched. In one sub-subclass of this subclass, the multilayer film isbiaxially stretched. In one sub-subclass of this subclass, themultilayer film is 45 degree stretched.

In one subclass of this class, the multilayer film has an in-planeretardation (R_(e)) of about 50 to about 160 nm and an out-of-planeretardation (R_(th)) of about −200 to about 20 nm at the wavelength (λ)550 nm, and a positive in-plane retardation (R_(e)) that satisfies therelations of 0.7<R_(e)(450)/R_(e)(550)<1 and1<R_(e)(650)/R_(e)(550)<1.25, wherein R_(e)(450), R_(e)(550), andR_(e)(650) are in-plane retardations measured at the light wavelengthsof 450 nm, 550 nm, and 650 nm respectively. In one sub-subclass of thissubclass, the film has a thickness in the range of from about 1 μm toabout 20 μm. In one sub-subclass of this subclass, the multilayer filmis uniaxially stretched. In one sub-subclass of this subclass, themultilayer film is biaxially stretched. In one sub-subclass of thissubclass, the multilayer film is 45 degree stretched.

In one subclass of this class, the multilayer film has an in-planeretardation (R_(e)) of about 50 to about 160 nm and an out-of-planeretardation (R_(th)) of about −20 to about −200 nm at the wavelength (λ)550 nm, and a positive in-plane retardation (R_(e)) that satisfies therelations of 0.75<R_(e)(450)/R_(e)(550)<0.9 and1.05<R_(e)(650)/R_(e)(550)<1.2, wherein R_(e)(450), R_(e)(550), andR_(e)(650) are in-plane retardations measured at the light wavelengthsof 450 nm, 550 nm, and 650 nm respectively. In one sub-subclass of thissubclass, the film has a thickness in the range of from about 1 μm toabout 20 μm. In one sub-subclass of this subclass, the multilayer filmis uniaxially stretched. In one sub-subclass of this subclass, themultilayer film is biaxially stretched. In one sub-subclass of thissubclass, the multilayer film is 45 degree stretched.

In various embodiments, additives such as plasticizers, stabilizers, UVabsorbers, antiblocks, slip agents, lubricants, dyes, pigments,retardation modifiers, etc. may be mixed with the regioselectivelysubstituted cellulose esters used in preparing the above-describedoptical films. Examples of these additives can be found, for example, inU.S. Patent Application Publication Nos. US 2009/0050842, US2009/0054638, and US 2009/0096962, the contents of which areincorporated herein by reference.

Any of the above-described films can be made by solvent casting, meltextrusion, lamination, or a coating process. These procedures aregenerally known in the art. Examples of solvent casting, melt extrusion,lamination, and coating methods can be found, for example, in U.S.Patent Application Publication Nos. US 2009/0050842, US 2009/0054638,and US 2009/0096962, the contents of which are incorporated herein byreference. Further examples of solvent casting, melt extrusion,lamination, and coating methods to form films can be found, for example,in U.S. Pat. Nos. 4,592,885 and 7,172,713, and U.S. Patent ApplicationPublication Nos. US 2005/0133953 and US 2010/0055356, the contents ofwhich are incorporated herein by reference.

In order to assist in obtaining the desired R_(e) and R_(th) valuesusing the regioselectively substituted cellulose esters describedherein, the films (single layer or multilayer) can be stretched. Byadjusting the stretch conditions, such as stretch temperature, stretchtype (45 degree, uniaxial or biaxial), stretch ratio, pre-heat time andtemperature, and post-stretch annealing time and temperature, thedesired R_(e), and R_(th), can be achieved. The precise stretchingconditions may depend upon the specific composition of theregioselectively substituted cellulose ester, the amount and type ofplasticizer, and the glass transition temperature of that specificcomposition. Hence, the specific stretching conditions can vary widely.In various embodiments, the stretching temperature can be in the rangeof from about 160 to about 200° C. Additionally, the stretch ratio basedon 1.0 in the machine direction (“MD”) can range from about 1.3 to about2.0 in the transverse direction (“TD”). The pre-heat time can be in therange of from about 10 to about 300 seconds, and the pre-heattemperature can be the same as the stretch temperature. Thepost-annealing time can range from about 0 to about 300 seconds, and thepost-annealing temperature can range from about 10 to about 40° C. belowthe stretching temperature. Film thickness may depend upon the filmthickness before stretching and upon the stretching conditions. Afterstretching, the film thickness can be from about 1 μm to about 500 μm,from about 5 μm to about 200 μm, or from about 10 μm to about 120 μm,from about 20 μm to about 100 μm, from about 30 μm to about 80 μm, orfrom about 40 μm to about 60 μm.

In addition to the optical properties, the films prepared from theregioselectively substituted cellulose esters described herein haveother valuable features. Many conventional cellulose esters used in LCDdisplays have relatively high moisture uptake which affects dimensionalstability and results in changing optical values of the film. Filmsprepared from the regioselectively substituted cellulose estersdescribed herein have low moisture uptake, and the optical values of thefilm change very little at high humidity and temperature. Thus, invarious embodiments, the regioselectively substituted cellulose esterscan contain less than 2 weight percent moisture, less than 1 weightpercent moisture, or less than 0.5 weight percent moisture. In othervarious embodiments, the change in R_(e) for the cellulose ester filmcan be less than 4 percent, less than 1 percent, or less than 0.5percent when stored at 60° C., 100 percent relative humidity for 240hours.

The regioselectively substituted cellulose esters described herein aresurprisingly thermally stable which makes them very useful in meltextrusion of film. Thus, one aspect of the present invention relates toregioselectively substituted cellulose esters that have less than 10percent weight loss by thermogravimetric analysis at 330° C., 340° C.,or 350° C.

The films of the current invention can be used as optical compensationfilms. The optical compensation films described herein can be employedin LCDs. Particularly, the above-described optical films can be employedas part or all of a compensation film in the polarizer stack of an LCD.As described above, polarizer stacks generally include two crossedpolarizers disposed on either side of a liquid crystal layer.Compensation films can be disposed between the liquid crystal layer andone of the polarizers. In one or more embodiments, the above-describedsingle layer optical film can be employed by itself as a compensationfilm (i.e., a waveplate) in an LCD. In such an embodiment, the singlelayer optical film can be disposed between the liquid crystal layer andone of the polarizing filters of the LCD. In other embodiments, theabove-described positive A-plate can be employed in a compensation film(i.e., a waveplate) in an LCD. In such embodiments, the A-plate can bedisposed adjacent to at least one additional optical film, where suchadditional optical film can be a positive C-plate. In any of theforegoing embodiments, LCDs prepared comprising the optical filmsdescribed herein can operate in in-plane-switching (“IPS”) mode.

The optical compensation film described herein can also be employed inOLED. For example, a QWP combined with a linear polarizer to form acircular polarizer. When the circular polarizer is put in front of anOLED device, it can reduce the ambient light reflected from OLED metalelectrodes to improved viewing quality, such as high contrast ratio andless color shift, especially when the QWP has a reverse dispersion closeto ideal.

The optical compensation films described herein can also be employed incircular polarizers. Particularly, a single quarter waveplate can beprepared comprising one or more of the above-described polymer films ofthe present invention, which can be used to convert linear polarizedlight to circular polarized light. This aspect may be particularlyvaluable for use in circular-polarized 3-dimensional (“3-D”) glassesand/or 3-D media displays, such as televisions (“3-D TV”). Accordingly,in one or more embodiments, a single quarter waveplate can be preparedcomprising the above-described single layer optical film. In othervarious embodiments, a single quarter waveplate can be preparedcomprising the above-described positive A-plate. Such quarter waveplatescan be applied to the glass of a 3-D TV, such as above the polarizingstack. Additionally, such quarter waveplates can be applied to the glassof 3-D glasses. In the case of 3-D glasses, the optical film can beapplied so that the optical axis in one lens is perpendicular orsubstantially perpendicular to the optical axis of the other lens. Theresult in 3-D glasses is that certain observed polarization is blockedin one lens but will pass through the other lens leading to the observed3-D optical effect. In various embodiments, a quarter waveplatecomprising one or more of the above-described optical films can beemployed in conjunction with at least one additional polarizer, whichcan be a linear polarizer.

The optical compensation film in accordance with the present inventionhas a positive in-plane retardation (R_(e)) and a reversed in-planewavelength dispersion characteristic, in which the value of phaseretardation is decreasingly positive toward shorter wavelengths. Forbilayer and multilayer films, this dispersion characteristic isexpressed by the ratios of the retardations as measured at thewavelengths of 450 nm, 550 nm, and 650 nm, which satisfy the relationsof R_(e)(450)/R_(e)(550)<1 and R_(e)(650)/R_(e)(550)>1. The ratio ofR_(e)(450)/R_(e)(550) can be 0.71 to 0.99, 0.72 to 0.98, 0.74 to 0.97,0.76 to 0.96, 0.78 to 0.95, 0.8 to 0.9, or 0.81 to 0.85. The ratio ofR_(e)(650)/R_(e)(550) can be 1.01 to 1.24, 1.02 to 1.23, 1.03 to 1.22,1.04 to 1.21, 1.05 to 1.2, or 1.1 to 1.19.

In one embodiment, the optical compensation film of the invention has anin-plane retardation (R_(e)) of about 50 to about 160 nm at thewavelength (λ) 550 nm. In another embodiment, the polymer film has anout-of-plane retardation (R_(th)) of about 0 to about −200 nm at thewavelength (λ) 550 nm. In yet another embodiment, the polymer film has apositive in-plane retardation that satisfies the relations of0.7<R_(e)(450)/R_(e)(550)<1 and 1<R_(e)(650)/R_(e)(550)<1.25, whereinR₄₅₀, R₅₅₀, and R₆₅₀ are in-plane retardations at the light wavelengthsof 450 nm, 550 nm, and 650 nm respectively. In an embodiment, thepolymer film has a positive in-plane retardation that satisfies therelations of 0.75<R_(e)(450)/R_(e)(550)<0.9 and1.05<R_(e)(650)/R_(e)(550)<1.2. In any one of the embodiments specifiedabove, the polymer film can be a positive A-plate having a refractiveindex profile of n_(x)>n_(y)=n_(z) and a reversed wavelength dispersion.

In one aspect, the first polymer film and the second polymer film in theabove-described optical compensation films are attached by lamination.In another aspect, the second polymer is coated on the first polymerfilm by solution cast.

In other embodiments, the retardation or the dispersion characteristicsof the optical compensation film can be further enhanced by introducingan additive, such as a small molecule or a polymer, to the multilayerfilm of the invention before stretching. Desirably, the additive has arigid rod-like moiety that is capable of being aligned in the plane ofthe film upon stretching. The chemical structure of the rigid rod-likemoiety is not particularly limited.

The film of the present invention may be formed into a multilayer filmby lamination or co-extrusion of the film of the present invention oneor more of another film. The multilayer film can be obtained by solutioncasting whereby one film is first solution cast and another film issolution casted onto the first film formed by solution casting. In oneembodiment, the first or the second solution cast film is a film of thepresent invention.

The present application also discloses a multilayer film comprising:

-   (1) a layer (A) comprising a regioselectively substituted cellulose    ester comprising: (a) a plurality of chromophore-acyl substituents;    and (b) a plurality of pivaloyl substituents, wherein the cellulose    ester has a hydroxyl degree of substitution (“DS_(OH)”) in the range    of from about 0 to about 0.9, wherein the cellulose ester has a    pivaloyl degree of substitution (“DS_(Pv)”) in the range of from    about 0.1 to about 1.2, wherein the cellulose ester has a    chromophore-acyl degree of substitution (“DS_(Ch)”) in the range of    from about 0.4 to about 1.6, and wherein the regioselectivity is    such that the sum of the chromophore-acyl degree of substitution at    C2 and C3 (“C2DS_(Ch)” and “C3DS_(Ch)”) minus the chromophore-acyl    degree of substitution at C6 (“C6DS_(Ch)”) is between about 0.1 and    about 1.6, wherein the chromophore-acyl is chosen from an    (C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or substituted    by 1-5 R¹; a heteroaryl-acyl, wherein the heteroaryl is a 5- to    10-membered ring having 1- to 4-heteroatoms chosen from N, O, or S,    and wherein the heteroaryl is unsubstituted or substituted by 1-5    R¹;

-    wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is    unsubstituted or substituted by 1-5 R¹; or

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from nitro, cyano, (C₁₋₆)alkyl; halo(C₁₋₆)alkyl;(C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl; (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo; 5-to 10-membered heteroaryl having 1-4 heteroatoms chosen from N, O, or S;or

and

-   (2) a layer (B) comprising a cellulose ester, a polycarbonate, a    polyester, a polyimide, a cycloolefin polymer, a cycloolefin    copolymer, or combinations thereof.

In one embodiment, the layer (B) comprises a cellulose ester comprisinga plurality of (C₁₋₆)alkyl-CO— substituents, wherein the cellulose esterhas a hydroxyl degree of substitution (“DS_(OH)2”) in the range of fromabout 0.25 to about 1.30, wherein the cellulose ester has an(C₁₋₆)alkyl-CO-degree of substitution (“DS_(Acyl)”) in the range of fromabout 1.70 to about 2.75. In one class of this embodiment, the celluloseester is a cellulose acetate butyrate, a cellulose acetate, a celluloseacetate propionate, a cellulose propionate, a cellulose butyrate, orcombinations thereof. In one class of this embodiment, the celluloseester is a cellulose acetate butyrate. In one class of this embodiment,the cellulose ester is a cellulose acetate. In one class of thisembodiment, the cellulose ester is a cellulose acetate propionate. Inone class of this embodiment, the cellulose ester is, a cellulosepropionate. In one class of this embodiment, the cellulose ester is acellulose butyrate.

In one embodiment, the layer (B) comprises a polycarbonate. In oneembodiment, the layer (B) comprises a polyester. In one embodiment, thelayer (B) comprises a polyimide. In one embodiment, the layer (B)comprises a cycloolefin polymer. In one embodiment, the layer (B)comprises a cycloolefin copolymer.

In one embodiment, the multilayer film is made by a solvent co-casting,a melt co-extrusion, a lamination or a coating process. In one class ofthis embodiment, the multilayer film is made by a solvent co-castingprocess. In one class of this embodiment, the multilayer film is made bya melt co-extrusion process. In one class of this embodiment, themultilayer film is made by a lamination process. In one class of thisembodiment, the multilayer film is made by a coating process.

In one embodiment, the multilayer film comprises one layer (A) and onelayer (B) in an A-B configuration. In one embodiment, the multilayerfilm comprising two layers (λ) and one layer (B) in an A-B-Aconfiguration.

In one embodiment, the multilayer film has been stretched in at leastone direction. In one embodiment, the multilayer film has been 45degree, uniaxially, or biaxially stretched. In one class of thisembodiment, the multilayer film has been 45 degree stretched. In oneclass of this embodiment, the multilayer film has been uniaxiallystretched. In one class of this embodiment, the multilayer film has beenbiaxially stretched.

In one embodiment, the multilayer film has an out-of-plane retardation(“R_(th)”) is in the range of from about −300 nm to about 0 nm, asmeasured at 589 nm at a thickness in the range of from about 20 μm toabout 140 μm, wherein the multilayer film stretched. In one class ofthis embodiment, the multilayer film is uniaxially, biaxially, or 45degree stretched. In one class of this embodiment, the multilayer filmhas a thickness in the range of from about 20 μm to about 140 μm. In onesubclass of this class, the film has a thickness in the range of fromabout 1 μm to about 20 μm. In one subclass of this class, the multilayerfilm is uniaxially, biaxially, or 45 degree stretched.

In one embodiment, the multilayer film has an out-of-plane retardation(“R_(th)”) measured at 589 nm is in the range of from about −200 nm toabout −50 nm, as measured at 589 nm at a thickness in the range of fromabout 20 μm to about 140 μm, wherein the multilayer film is a stretched.In one class of this embodiment, the multilayer film is uniaxially,biaxially, or 45 degree stretched. In one class of this embodiment, themultilayer film has a thickness in the range of from about 20 μm toabout 140 μm. In one subclass of this class, the layer (A) has athickness in the range of from about 1 μm to about 20 μm. In onesubclass of this class, the multilayer film is uniaxially, biaxially, or45 degree stretched.

In one embodiment, the multilayer film has in-plane retardation (R_(e))in the range of about 40 to about 160 nm, in the range of about 50 to150 nm, in the range of about 100 to 150 nm or in the range of about 110to 150 nm and out-of-plane retardation (R_(th)) of about 0 to about −200nm, in the range of about 0 to −150 nm or in the range of about −30 to−100 nm at the wavelength (λ) 550 nm. In one class of this embodiment,the multilayer film is uniaxially, biaxially, or 45 degree stretched. Inone class of this embodiment, the multilayer film has a thickness in therange of from about 20 μm to about 140 μm. In one subclass of thisclass, the layer (A) has a thickness in the range of from about 1 μm toabout 20 μm. In one subclass of this class, the multilayer film isuniaxially, biaxially, or 45 degree stretched.

In one embodiment, the multilayer film has a positive in-planeretardation that satisfies the relations of 0.7<R_(e)(450)/R_(e)(550)<1and 1<R_(e)(650)/R_(e)(550)<1.25, wherein R_(e)(450), R_(e)(550), andR_(e)(650) are in-plane retardations at the light wavelengths of 450 nm,550 nm, and 650 nm, respectively. In one class of this embodiment, themultilayer film is uniaxially, biaxially, or 45 degree stretched. In oneclass of this embodiment, the multilayer film has a thickness in therange of from about 20 μm to about 140 μm. In one subclass of thisclass, the layer (A) has a thickness in the range of from about 1 μm toabout 20 μm. In one subclass of this class, the multilayer film isuniaxially, biaxially, or 45 degree stretched.

In one embodiment, the multilayer film has an in-plane retardation(R_(e)) of about 50 to about 160 nm at the light wavelength of 550 nm.In one embodiment of this film, the film has an out-of-plane retardation(R_(th)) of about −200 nm to about 0 nm at the light wavelength of 550nm. In one class of this embodiment, the multilayer film is uniaxially,biaxially, or 45 degree stretched. In one class of this embodiment, themultilayer film has a thickness in the range of from about 20 μm toabout 140 μm. In one subclass of this class, the layer (A) has athickness in the range of from about 1 μm to about 20 μm. In onesubclass of this class, the multilayer film is uniaxially, biaxially, or45 degree stretched.

In one embodiment, the multilayer film has an in-plane retardation(R_(e)) of about 50 to about 160 nm and out-of-plane retardation(R_(th)) of about −200 to about 20 nm as measured at the wavelength of550 nm. In one class of this embodiment, the multilayer film isuniaxially, biaxially, or 45 degree stretched. In one class of thisembodiment, the multilayer film has a thickness in the range of fromabout 20 μm to about 140 μm. In one subclass of this class, the layer(A) has a thickness in the range of from about 1 μm to about 20 μm. Inone subclass of this class, the multilayer film is uniaxially,biaxially, or 45 degree stretched.

In one embodiment, the multilayer film has an in-plane retardation(R_(e)) of about 50 to about 160 nm and an out-of-plane retardation(R_(th)) of about −200 to about 20 nm at the wavelength (λ) 550 nm, anda positive in-plane retardation (R_(e)) that satisfies the relations of0.7<R_(e)(450)/R_(e)(550)<1 and 1<R_(e)(650)/R_(e)(550)<1.25, whereinR_(e)(450), R_(e)(550), and R_(e)(650) are in-plane retardationsmeasured at the light wavelengths of 450 nm, 550 nm, and 650 nmrespectively. In one class of this embodiment, the multilayer film isuniaxially, biaxially, or 45 degree stretched. In one class of thisembodiment, the multilayer film has a thickness in the range of fromabout 20 μm to about 140 μm. In one subclass of this class, the layer(A) has a thickness in the range of from about 1 μm to about 20 μm. Inone subclass of this class, the multilayer film is uniaxially,biaxially, or 45 degree stretched.

In one embodiment, the multilayer film has an in-plane retardation(R_(e)) of about 50 to about 160 nm and an out-of-plane retardation(R_(th)) of about −20 to about −200 nm at the wavelength (λ) 550 nm, anda positive in-plane retardation (R_(e)) that satisfies the relations of0.75<R_(e)(450)/R_(e)(550)<0.9 and 1.05<R_(e)(650)/R_(e)(550)<1.2,wherein R_(e)(450), R_(e)(550), and R_(e)(650) are in-plane retardationsmeasured at the light wavelengths of 450 nm, 550 nm, and 650 nmrespectively. In one class of this embodiment, the multilayer film isuniaxially, biaxially, or 45 degree stretched. In one class of thisembodiment, the multilayer film has a thickness in the range of fromabout 20 μm to about 140 μm. In one subclass of this class, the layer(A) has a thickness in the range of from about 1 μm to about 20 μm. Inone subclass of this class, the multilayer film is uniaxially,biaxially, or 45 degree stretched.

In one embodiment, the multilayer film is an A-plate film. In one classof this embodiment, the multilayer film is uniaxially, biaxially, or 45degree stretched. In one class of this embodiment, the multilayer filmis uniaxially stretched. In one class of this embodiment, the multilayerfilm is biaxially stretched. In one class of this embodiment, themultilayer film is 45 degree stretched.

In one class of this embodiment, the A-plate film is a negative A-platefilm. In one subclass of this class, the multilayer film has a thicknessin the range of 20 μm to about 140 μm. In one sub-subclass of thissubclass, the multilayer film is 45 degree, uniaxially, or biaxiallystretched.

In one class of this embodiment, the A-plate film is a positive A-platefilm. In one subclass of this class, the multilayer film has a thicknessin the range of 20 μm to about 140 μm. In one sub-subclass of thissubclass, the multilayer film is 45 degree, uniaxially, or biaxiallystretched.

Process

The present application also discloses a process for the preparation ofa regioselectively substituted cellulose ester, the process comprising:

(1) contacting a nonregioselectively substituted cellulose ester(“NSCE”) with a deacylating agent (“DA”) under conditions sufficient toobtain a regioselectively deprotected cellulose ester (“RDCE”),

wherein the DA is added at one time or in consecutive stages,

wherein the DA is an amine compound,

wherein the C2 degree of substitution of the hydroxyl substituents(“C2DS_(OH)”) of the RDCE or the C3 degree of substitution of thehydroxyl substituents (“C3DS_(OH)”) of the RDCE is greater than the C6degree of substitution of the hydroxyl substituents (“C6DS_(OH)”) of theRDCE.

In one embodiment of this process, the C2DS_(OH) is greater than theC3S_(OH).

The conditions for the preparation of the RDCE are known to one ofordinary skill in the art. The conditions include adjusting thetemperature, time, solvents, sequence of additions, adding additives,and the like. The reaction temperature can be adjusted (e.g. in therange of from about 20° C. and about 80° C.). The time can be adjusted(e.g. in the range of from about 5 h to about 48 h). The solvent systemcan be adjusted (e.g., with or without a solvent and with solventmixtures). The additive can for example be an (C₂₋₈)alkanoic acid).

The RDCE can further be treated with acylating agents known to one ofordinary skill in the art to synthesize regioselectively substitutedcellulose esters.

In one embodiment of this process, the conditions includes adding an(C₂₋₈)alkanoic acid. In one class of this embodiment, the (C₂₋₈)alkanoicacid is chosen from acetic acid, propionic acid, butyric acid,isobutyric acid, valeric acid, capyrlic acid, pivalic acid, 1- or2-naphthoic acid, or benzoic acid. In one subclass of this class, theconditions also include a reaction temperature in the range of fromabout 25° C. to about 50° C. and a reaction time in the range of fromabout 15 h to about 24 h. In one sub-subclass of this subclass, the(C₂₋₈)alkanoic acid is acetic acid. In one sub-subclass of thissubclass, the (C₂₋₈)alkanoic acid is propionic acid. In one sub-subclassof this subclass, the (C₂₋₈)alkanoic acid is butyric acid. In onesub-subclass of this subclass, the (C₂₋₈)alkanoic acid is isobutyricacid. In one sub-subclass of this subclass, the (C₂₋₆)alkanoic acid isvaleric acid. In one sub-subclass of this subclass, the (C₂₋₈)alkanoicacid is caprylic acid. In one sub-subclass of this subclass, the(C₂₋₈)alkanoic acid is pivalic acid. In one sub-subclass of thissubclass, the (C₂₋₈)alkanoic acid is 1-naphthoic acid. In onesub-subclass of this subclass, the (C₂₋₈)alkanoic acid is 2-naphthoicacid. In one sub-subclass of this subclass, the (C₂₋₈)alkanoic acid isbenzoic acid.

In one embodiment of this process, the amine compound is chosen frommethylamine, ethylamine, hydroxylamine, hydrazine, and/or solvates,hydrates or salts thereof. In one class of this embodiment, the aminecompound is methylamine. In one class of this embodiment, the aminecompound is ethylamine. In one class of this embodiment, the aminecompound is hydroxylamine. In one class of this embodiment, the aminecompound is hydrazine.

In one class of this embodiment, the conditions also include a reactiontemperature in the range of from about 25° C. to about 50° C.; areaction time in the range of from about 15 h to about 24 h; and addingan (C₂₋₈)alkanoic acid.

In one subclass of this class, the amine compound is methylamine In onesubclass of this class, the amine compound is ethylamine. In onesubclass of this class, the amine compound is hydroxylamine. In onesubclass of this class, the amine compound is hydrazine.

In one embodiment of this process, the conditions include running thereaction without a solvent. In one class of this embodiment, theconditions also include a reaction temperature in the range of fromabout 25° C. to about 50° C.; a reaction time in the range of from about15 h to about 24 h; and adding an (C₂₋₈)alkanoic acid.

In one embodiment of this process, the conditions includes adding one ormore solvents chosen from an (C₁₋₈)alkanol, or pyridine. In one class ofthis embodiment, the conditions also include a reaction temperature inthe range of from about 25° C. to about 50° C.; a reaction time in therange of from about 15 h to about 24 h; and adding an (C₂₋₈)alkanoicacid.

In one class of this embodiment, the conditions also include a reactiontemperature in the range of from about 25° C. to about 50° C.; areaction time in the range of from about 15 h to about 24 h; and addingan (C₂₋₈)alkanoic acid.

In one class of this embodiment, the solvent is an (C₁₋₈)alkanol. In onesubclass of this class, the conditions also include a reactiontemperature in the range of from about 25° C. to about 50° C.; areaction time in the range of from about 15 h to about 24 h; and addingan (C₂₋₈)alkanoic acid.

In one subclass of this class, the (C₁₋₈)alkanol is chosen frommethanol, ethanol, propanol, isopropanol, butanol, or isobutanol. In onesub-subclass of this subclass, the conditions also include a reactiontemperature in the range of from about 25° C. to about 50° C.; areaction time in the range of from about 15 h to about 24 h; and addingan (C₂₋₈)alkanoic acid.

In one class of this embodiment, the solvent is a mixture ofdimethylsulfoxide and (C₁₋₈)alkanol. In one subclass of this class, theconditions also include a reaction temperature in the range of fromabout 25° C. to about 50° C.; a reaction time in the range of from about15 h to about 24 h; and adding an (C₂₋₈)alkanoic acid.

In one embodiment of this process, the conditions include a reactiontemperature in the range of from about 20° C. to about 80° C. In oneembodiment of this process, the conditions include a reactiontemperature in the range of from about 25° C. to about 50° C. In oneembodiment of this process, the conditions include a reactiontemperature in the range of from about 40° C. to about 50° C.

In one embodiment of this process, the DS_(OH) of the RDCE is in therange of from about 1.7 to about 1.9; and the C2DS_(OH)>C3DS_(OH); andC2DS_(OH) or C3DS_(OH)>C6DS_(OH). In one subclass of this class,C2DS_(OH)+C3DS_(OH)>C6DS_(OH).

In one embodiment of this process, the DS_(OH) of the RDCE is in therange of from about 1.8 to about 1.9; and the C2DS_(OH)>C3DS_(OH); andC2DS_(OH) or C3DS_(OH)>C6DS_(OH). In one subclass of this class,C2DS_(OH)+C3DS_(OH)>C6DS_(OH).

The present application discloses a process for the preparation of aregioselectively substituted cellulose ester comprising:

(1) contacting a regioselectively deprotected cellulose ester (“RDCE”)with a sterically hindered acylating agent (“SHAA”) in a solvent underconditions sufficient to obtain a first regioselectively substitutedcellulose ester (“FRSCE”), wherein the C2DS_(OH) or C3DS_(OH) of theRDCE is greater than the C6DS_(OH) of the RDCE, wherein the SHAA isadded at one time or in consecutive stages, and wherein the stericallyhindered acyl group is selective or partially selective for the primaryalcohol positions; and

(2) contacting the FRSCE with a first acylating agent (“FAA”) toregioselectively add a plurality of a first acyl group (“FAG”) underconditions sufficient to obtain a second regioselectively substitutedcellulose ester (“SRSCE”), wherein the FAG is selective for the C2 or C3alcohol position, and wherein the FAA is added at one time or inconsecutive stages.

In one embodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a transmission b* value that is less than 0.8. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a transmission b* value that is less than 0.7. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a transmission b* value that is less than 0.6. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a transmission b* value that is less than 0.5. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a transmission b* value that is less than 0.4. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a transmission b* value that is less than 0.3.

In one embodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 4.0. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 3.0. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 2.0. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 1.0. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 0.9. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 0.8. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 0.7. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 0.6. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substituted In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 0.5. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 0.4. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 0.3. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm. In oneembodiment of this process, when the regioselectively substitutedcellulose ester prepared from the process is formed into a film, thefilm has a percent haze of less than about 0.2. In one class of thisembodiment, the film has a thickness 1 μm to about 20 μm.

In one embodiment of this process, the RDCE is prepared by the processcomprising: contacting a nonregioselectively substituted cellulose esterwith a deacylating agent (“DA”) under conditions sufficient to obtainthe RDCE, wherein the DA is added at one time or in consecutive stages,wherein the DA is chosen from a fluoride salt, a hydroxide salt, or anamine compound, and wherein the regioselectively deprotected celluloseester has been selectively deprotected at the secondary alcoholpositions.

In one class of this embodiment, the DS_(OH) of the RDCE is in the rangeof from about 1.7 to about 1.9; and the C2DS_(OH)>C3DS_(OH); andC2DS_(OH) or C3DS_(OH)>C6DS_(OH). In one subclass of this class,C2DS_(OH)+C3DS_(OH)>C6DS_(OH).

In one class of this embodiment, the DS_(OH) of the RDCE is in the rangeof from about 1.8 to about 1.9; and the C2DS_(OH)>C3DS_(OH); andC2DS_(OH) or C3DS_(OH)>C6DS_(OH). In one subclass of this class,C2DS_(OH)+C3DS_(OH)>C6DS_(OH).

In one embodiment of this process, the SHAA is chosen from pivaloylanhydride or a pivaloyl halide. In one class of this embodiment, theSHAA is present in the range of from about 0.2 to about 0.5 eq. In onesubclass of this class, the FAA is chosen from acetyl anhydride, anacetyl halide, propionyl anhydride, propionyl halide, butyryl anhydride,burtyryl halide, isobutyroyl anhydride, isobutyroyl halide, anunsubstituted or substituted benzoyl anhydride, an unsubstituted orsubstituted benzoyl halide, an unsubstituted or substituted naphthoylanhydride, or an unsubstituted or substituted naphthoyl halide, and theFAA is present in the range of from about 0.2 to about 2.0 eq. In onesub-subclass of this subclass, the FAA is 1-naphthoyl anhydride or2-naphthoyl anhydride. In one sub-sub-subclass of this sub-subclass, thesolvent is chosen from methyl ethyl ketone, acetone, tetrahydrofuran,pyridine, substituted pyridine, 1,3-dimethyl-2-imidazolidinone,dimethylacetamide, dioxane, dimethylformamide, ethyl acetate, butylacetate, methylisobutyl ketone, N-methylimidazole, N-methylpyrrolidone,trichloromethane, or dichloromethane. In one sub-subclass of thissubclass, the FAA is 1-naphthoyl halide or 2-naphthoyl halide. In onesub-sub-subclass of this sub-subclass, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one sub-subclass of this subclass, the FAA isbenzoyl anhydride. In one sub-sub-subclass of this sub-subclass, thesolvent is chosen from methyl ethyl ketone, acetone, tetrahydrofuran,pyridine, substituted pyridine, 1,3-dimethyl-2-imidazolidinone,dimethylacetamide, dioxane, dimethylformamide, ethyl acetate, butylacetate, methylisobutyl ketone, N-methylimidazole, N-methylpyrrolidone,trichloromethane, or dichloromethane. In one sub-subclass of thissubclass, the FAA is benzoyl halide. In one sub-sub-subclass of thissub-subclass, the solvent is chosen from methyl ethyl ketone, acetone,tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one subclass of this class, the FAA is chromophore-acyl-X, wherein: Xis chloro, bromo, or iodo; and chromophore-acyl is chosen from (i) an(C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or substituted by1-5 R¹; (ii) a heteroaryl-acyl, wherein the heteroaryl is a 5- to10-membered ring having 1- to 4-heteroatoms chosen from N, O, or S, andwherein the heteroaryl is unsubstituted or substituted by 1-5 R¹;

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹; or

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from nitro, cyano, (C₁₋₆)alkyl; halo(C₁₋₆)alkyl;(C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl; (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo; 5-to 10-membered heteroaryl having 1-4 heteroatoms chosen from N, O, or S;or

In one sub-subclass of this subclass, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one sub-subclass of this subclass, the chromophore-acyl is an(C₆₋₂₀)aryl-acyl. In one sub-subclass of this subclass, thechromophore-acyl is a heteroaryl-acyl. In one sub-subclass of thissubclass, the chromophore-acyl is

In one sub-subclass of this subclass, the chromophore-acyl is

In one class of this embodiment, the SHAA is present in the range offrom about 0.3 to about 0.5 eq. In one subclass of this class, the FAAis chosen from acetyl anhydride, an acetyl halide, propionyl anhydride,propionyl halide, butyryl anhydride, burtyryl halide, isobutyroylanhydride, isobutyroyl halide, an unsubstituted or substituted benzoylanhydride, an unsubstituted or substituted benzoyl halide, anunsubstituted or substituted naphthoyl anhydride, or an unsubstituted orsubstituted naphthoyl halide, and the FAA is present in the range offrom about 0.2 to about 2.0 eq. In one sub-subclass of this subclass,the FAA is 1-naphthoyl anhydride or 2-naphthoyl anhydride. In onesub-sub-subclass of this sub-subclass, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one sub-subclass of this subclass, the FAA is1-naphthoyl halide or 2-naphthoyl halide. In one sub-sub-subclass ofthis sub-subclass, the solvent is chosen from methyl ethyl ketone,acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one sub-subclass of this subclass, the FAA isbenzoyl anhydride. In one sub-sub-subclass of this sub-subclass, thesolvent is chosen from methyl ethyl ketone, acetone, tetrahydrofuran,pyridine, substituted pyridine, 1,3-dimethyl-2-imidazolidinone,dimethylacetamide, dioxane, dimethylformamide, ethyl acetate, butylacetate, methylisobutyl ketone, N-methylimidazole, N-methylpyrrolidone,trichloromethane, or dichloromethane. In one sub-subclass of thissubclass, the FAA is benzoyl halide. In one sub-sub-subclass of thissub-subclass, the solvent is chosen from methyl ethyl ketone, acetone,tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one subclass of this class, the FAA is chromophore-acyl-X, wherein: Xis chloro, bromo, or iodo; and chromophore-acyl is chosen from (i) an(C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or substituted by1-5 R¹; (ii) a heteroaryl-acyl, wherein the heteroaryl is a 5- to10-membered ring having 1- to 4-heteroatoms chosen from N, O, or S, andwherein the heteroaryl is unsubstituted or substituted by 1-5 R¹;

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹; or

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from nitro, cyano, (C₁₋₆)alkyl; halo(C₁₋₆)alkyl;(C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl; (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo; 5-to 10-membered heteroaryl having 1-4 heteroatoms chosen from N, O, or S;or

In one sub-subclass of this subclass, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one sub-subclass of this subclass, the chromophore-acyl is an(C₆₋₂₀)aryl-acyl. In one sub-sub-subclass of this sub-subclass, thechromophore-acyl is a heteroaryl-acyl. In one sub-sub-subclass of thissub-subclass, the chromophore-acyl is

In one sub-sub-subclass of this sub-subclass, the chromophore-acyl is

In one embodiment of this process, the SHAA is pivaloyl anhydride. Inone class of this embodiment, the SHAA is present in the range of fromabout 0.2 to about 0.5 eq. In one subclass of this class, the FAA ischosen from acetyl anhydride, an acetyl halide, propionyl anhydride,propionyl halide, butyryl anhydride, burtyryl halide, isobutyroylanhydride, isobutyroyl halide, an unsubstituted or substituted benzoylanhydride, an unsubstituted or substituted benzoyl halide, anunsubstituted or substituted naphthoyl anhydride, or an unsubstituted orsubstituted naphthoyl halide, and the FAA is present in the range offrom about 0.2 to about 2.0 eq. In one sub-subclass of this subclass,the FAA is 1-naphthoyl anhydride or 2-naphthoyl anhydride. In onesub-sub-subclass of this sub-subclass, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one sub-subclass of this subclass, the FAA is1-naphthoyl halide or 2-naphthoyl halide. In one sub-sub-subclass ofthis sub-subclass, the solvent is chosen from methyl ethyl ketone,acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one sub-subclass of this subclass, the FAA isbenzoyl anhydride. In one sub-sub-subclass of this sub-subclass, thesolvent is chosen from methyl ethyl ketone, acetone, tetrahydrofuran,pyridine, substituted pyridine, 1,3-dimethyl-2-imidazolidinone,dimethylacetamide, dioxane, dimethylformamide, ethyl acetate, butylacetate, methylisobutyl ketone, N-methylimidazole, N-methylpyrrolidone,trichloromethane, or dichloromethane. In one sub-subclass of thissubclass, the FAA is benzoyl halide. In one sub-sub-subclass of thissub-subclass, the solvent is chosen from methyl ethyl ketone, acetone,tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one subclass of this class, the FAA is chromophore-acyl-X, wherein: Xis chloro, bromo, or iodo; and chromophore-acyl is chosen from (i) an(C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or substituted by1-5 R¹; (ii) a heteroaryl-acyl, wherein the heteroaryl is a 5- to10-membered ring having 1- to 4-heteroatoms chosen from N, O, or S, andwherein the heteroaryl is unsubstituted or substituted by 1-5 R¹;

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹; or

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from nitro, cyano, (C₁₋₆)alkyl; halo(C₁₋₆)alkyl;(C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl; (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo; 5-to 10-membered heteroaryl having 1-4 heteroatoms chosen from N, O, or S;or

In one sub-subclass of this subclass, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one sub-subclass of this subclass, the chromophore-acyl is an(C₆₋₂₀)aryl-acyl. In one sub-sub-subclass of this sub-subclass, thechromophore-acyl is a heteroaryl-acyl. In one sub-sub-subclass of thissub-subclass, the chromophore-acyl is

In one sub-sub-subclass of this sub-subclass, the chromophore-acyl is

In one class of this embodiment, the SHAA is present in the range offrom about 0.3 to about 0.5 eq. In one subclass of this class, the FAAis chosen from acetyl anhydride, an acetyl halide, propionyl anhydride,propionyl halide, butyryl anhydride, burtyryl halide, isobutyroylanhydride, isobutyroyl halide, an unsubstituted or substituted benzoylanhydride, an unsubstituted or substituted benzoyl halide, anunsubstituted or substituted naphthoyl anhydride, or an unsubstituted orsubstituted naphthoyl halide, and the FAA is present in the range offrom about 0.2 to about 2.0 eq. In one sub-subclass of this subclass,the FAA is 1-naphthoyl anhydride or 2-naphthoyl anhydride. In onesub-sub-subclass of this sub-subclass, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one sub-subclass of this subclass, the FAA is1-naphthoyl halide or 2-naphthoyl halide. In one sub-sub-subclass ofthis sub-subclass, the solvent is chosen from methyl ethyl ketone,acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one sub-subclass of this subclass, the FAA isbenzoyl anhydride. In one sub-sub-subclass of this sub-subclass, thesolvent is chosen from methyl ethyl ketone, acetone, tetrahydrofuran,pyridine, substituted pyridine, 1,3-dimethyl-2-imidazolidinone,dimethylacetamide, dioxane, dimethylformamide, ethyl acetate, butylacetate, methylisobutyl ketone, N-methylimidazole, N-methylpyrrolidone,trichloromethane, or dichloromethane. In one sub-subclass of thissubclass, the FAA is benzoyl halide. In one sub-sub-subclass of thissub-subclass, the solvent is chosen from methyl ethyl ketone, acetone,tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one subclass of this class, the FAA is chromophore-acyl-X, wherein: Xis chloro, bromo, or iodo; and chromophore-acyl is chosen from (i) an(C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or substituted by1-5 R¹; (ii) a heteroaryl-acyl, wherein the heteroaryl is a 5- to10-membered ring having 1- to 4-heteroatoms chosen from N, O, or S, andwherein the heteroaryl is unsubstituted or substituted by 1-5 R¹;

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹; or

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from nitro, cyano, (C₁₋₆)alkyl; halo(C₁₋₆)alkyl;(C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl; (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo; 5-to 10-membered heteroaryl having 1-4 heteroatoms chosen from N, O, or S;or

In one sub-subclass of this subclass, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one sub-subclass of this subclass, the chromophore-acyl is an(C₆₋₂₀)aryl-acyl. In one sub-sub-subclass of this sub-subclass, thechromophore-acyl is a heteroaryl-acyl. In one sub-sub-subclass of thissub-subclass, the chromophore-acyl is

In one sub-sub-subclass of this sub-subclass, the chromophore-acyl is

In one embodiment of this process, the SHAA is a pivaloyl halide. In oneclass of this embodiment, the SHAA is present in the range of from about0.2 to about 0.5 eq. In one subclass of this class, the FAA is chosenfrom acetyl anhydride, an acetyl halide, propionyl anhydride, propionylhalide, butyryl anhydride, burtyryl halide, isobutyroyl anhydride,isobutyroyl halide, an unsubstituted or substituted benzoyl anhydride,an unsubstituted or substituted benzoyl halide, an unsubstituted orsubstituted naphthoyl anhydride, or an unsubstituted or substitutednaphthoyl halide, and the FAA is present in the range of from about 0.2to about 2.0 eq. In one sub-subclass of this subclass, the FAA is1-naphthoyl anhydride or 2-naphthoyl anhydride. In one sub-sub-subclassof this sub-subclass, the solvent is chosen from methyl ethyl ketone,acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one sub-subclass of this subclass, the FAA is1-naphthoyl halide or 2-naphthoyl halide. In one sub-sub-subclass ofthis sub-subclass, the solvent is chosen from methyl ethyl ketone,acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one sub-subclass of this subclass, the FAA isbenzoyl anhydride. In one sub-sub-subclass of this sub-subclass, thesolvent is chosen from methyl ethyl ketone, acetone, tetrahydrofuran,pyridine, substituted pyridine, 1,3-dimethyl-2-imidazolidinone,dimethylacetamide, dioxane, dimethylformamide, ethyl acetate, butylacetate, methylisobutyl ketone, N-methylimidazole, N-methylpyrrolidone,trichloromethane, or dichloromethane. In one sub-subclass of thissubclass, the FAA is benzoyl halide. In one sub-sub-subclass of thissub-subclass, the solvent is chosen from methyl ethyl ketone, acetone,tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one subclass of this class, the FAA is chromophore-acyl-X, wherein: Xis chloro, bromo, or iodo; and chromophore-acyl is chosen from (i) an(C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or substituted by1-5 R¹; (ii) a heteroaryl-acyl, wherein the heteroaryl is a 5- to10-membered ring having 1- to 4-heteroatoms chosen from N, O, or S, andwherein the heteroaryl is unsubstituted or substituted by 1-5 R¹;

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹; or

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from nitro, cyano, (C₁₋₆)alkyl; halo(C₁₋₆)alkyl;(C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl; (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo; 5-to 10-membered heteroaryl having 1-4 heteroatoms chosen from N, O, or S;or

In one sub-subclass of this subclass, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane.

In one sub-subclass of this subclass, the chromophore-acyl is an(C₆₋₂₀)aryl-acyl. In one sub-sub-subclass of this sub-subclass, thechromophore-acyl is a heteroaryl-acyl. In one sub-sub-subclass of thissub-subclass, the chromophore-acyl is

In one sub-sub-subclass of this sub-subclass, the chromophore-acyl is

In one embodiment of this process, the solvent is chosen from methylethyl ketone, acetone, tetrahydrofuran, pyridine, substituted pyridine,1,3-dimethyl-2-imidazolidinone, dimethylacetamide, dioxane,dimethylformamide, ethyl acetate, butyl acetate, methylisobutyl ketone,N-methylimidazole, N-methylpyrrolidone, trichloromethane, ordichloromethane. In one class of this embodiment, the solvent is chosenfrom pyridine, dimethylacetamide, dimethylformamide orN-methylimidazole.

In one embodiment of this process, the FAA is chosen from acetylanhydride, an acetyl halide, propionyl anhydride, propionyl halide,butyryl anhydride, butyryl halide, isobutyroyl anhydride, isobutyroylhalide, an unsubstituted or substituted benzoyl anhydride, anunsubstituted or substituted benzoyl halide, an unsubstituted orsubstituted naphthoyl anhydride, or an unsubstituted or substitutednaphthoyl halide. In one class of this embodiment, the FAA is present inthe range of from about 0.2 to about 2.0 eq.

In one embodiment of this process, the FAA is an unsubstituted orsubstituted benzoyl anhydride, an unsubstituted or substituted benzoylhalide, an unsubstituted or substituted naphthoyl anhydride or anunsubstituted or substituted naphthoyl halide.

In one embodiment of this process, the FAA is an unsubstituted orsubstituted benzoyl anhydride. In one class of this embodiment, the FAAis present in the range of from about 0.2 to about 2.0 eq. In one classof this embodiment, the unsubstituted or substituted benzoyl anhydrideis chosen from benzoyl anhydride or 2-(benzothiazol-2-yl)benzoylanhydride. In one subclass of this class, the FAA is present in therange of from about 0.2 to about 2.0 eq.

In one embodiment of this process, the FAA is an unsubstituted orsubstituted benzoyl halide. In one class of this embodiment, the FAA ispresent in the range of from about 0.2 to about 2.0 eq. In one classembodiment of this process, the unsubstituted or substituted benzoylhalide is chosen from benzoyl halide or 2-(benzothiazol-2-yl)benzoylhalide. In one subclass of this class, the FAA is present in the rangeof from about 0.2 to about 2.0 eq.

In one embodiment of this process, the FAA is an unsubstituted orsubstituted naphthoyl anhydride. In one class of this embodiment, theFAA is present in the range of from about 0.2 to about 2.0 eq. In oneclass of this embodiment, the unsubstituted or substituted naphthoylanhydride is chosen from 1-naphthoyl anhydride or 2-naphthoyl anhydride.In one subclass of this class, the FAA is present in the range of fromabout 0.2 to about 2.0 eq.

In one embodiment of this process, the FAA is an unsubstituted orsubstituted naphthoyl halide. In one class of this embodiment, the FAAis present in the range of from about 0.2 to about 2.0 eq. In one classof this embodiment, the unsubstituted or substituted naphthoyl chlorideis chosen from 1-naphthoyl halide or 2-naphthoyl halide. In one subclassof this class, the FAA is present in the range of from about 0.2 toabout 2.0 eq.

In one embodiment of this process, the FAA is a chromophore-acyl-X,wherein:

X is chloro, bromo, or iodo; and chromophore-acyl is chosen from (i) an(C₆₋₂₀)aryl-acyl, wherein the aryl is unsubstituted or substituted by1-5 R¹; (ii) a heteroaryl-acyl, wherein the heteroaryl is a 5- to10-membered ring having 1- to 4-heteroatoms chosen from N, O, or S, andwherein the heteroaryl is unsubstituted or substituted by 1-5 R¹;

wherein the aryl is a C₁₋₆ aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹; or

wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from nitro, cyano, (C₁₋₆)alkyl; halo(C₁₋₆)alkyl;(C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl; (C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo; 5-to 10-membered heteroaryl having 1-4 heteroatoms chosen from N, O, or S;or

In one class of this embodiment, the FAA is present in the range of fromabout 0.2 to about 2.0 eq.

In one class of this embodiment, the chromophore-acyl is aheteroaryl-acyl. In one subclass of this class, the FAA is present inthe range of from about 0.2 to about 2.0 eq.

In one class of this embodiment, the chromophore-acyl is

In one subclass of this class, the FAA is present in the range of fromabout 0.2 to about 2.0 eq.

In one class of this embodiment, the chromophore-acyl is

In one subclass of this class, the FAA is present in the range of fromabout 0.2 to about 2.0 eq.

In one embodiment of this process, the process further comprising (3)contacting the SRSCE with a second acylating agent (“SAA”) underconditions sufficient to obtain a third regioselectively substitutedcellulose ester (“TRSCE”), wherein the SAA is added at one time or inconsecutive stages. In one class of this embodiment, the SAA iscontacting the SRSCE after the FAA is at least substantially consumed.In one class of this embodiment, the SAA is contacting the SRSCE beforethe FAA is substantially consumed.

This invention can be further illustrated by the following examples ofembodiments thereof, although it will be understood that these examplesare included merely for the purposes of illustration and are notintended to limit the scope of the invention unless otherwisespecifically indicated.

EXAMPLES Materials and Methods

General Procedures:

NMR Characterization: Proton NMR data were obtained on a JEOL ModelEclipse-600 NMR spectrometer operating at 600 MHz. The sample tube sizewas 5 mm, and the sample concentrations were ca. 20 mg/mL DMSO-d₆. Eachspectrum was recorded at 80° C. using 64 scans and a 15 second pulsedelay. One to two drops of trifluoroacetic acid-d were added to eachsample to shift residual water from the spectral region of interest.Chemical shifts are reported in parts per million (“ppm”) fromtetramethylsilane with the center peak of DMSO-d₆ as an internalreference (2.49 ppm).

Quantitative ¹³C NMR data were obtained on a JEOL Model GX-400 NMRspectrometer operating at 100 MHz. The sample tube size was 10 mm, andthe sample concentrations were ca. 100 mg/mL DMSO-d₆. Chromium(III)acetylacetonate was added to each sample at 5 mg/100 mg cellulose esteras a relaxation agent. Each spectrum was typically recorded at 80° C.using 10000 scans and a 1 second pulse delay. Chemical shifts arereported in ppm from tetramethylsilane with the center peak of DMSO-d₆as an internal reference (39.5 ppm).

The proton and carbon NMR assignments, the degree of substitution andthe relative degree of substitution (“RDS”) of the various acyl groupsof the cellulose esters were determined by adapting the proceduresdisclosed in US 2012/0262650.

The solutions of the cellulose esters for preparation of the films andthe film preparation were made by adapting the procedures disclosed inUS 2012/0262650.

Abbreviations

AcOH is acetic acid; adj is adjusted; ArCl is aryl-acyl chloride; Bt is(2-benzothiazol-2-yl)benzoyl; BtCl is 2-(benzothiazol-2-yl)benzoylchloride; Bz is benzoyl; BzCl is benzoyl chloride; ° C. is degree(s)Celsius; CPPvNp is a propionyl, pivolyl, and naphthoyl substitutedcellulose ester; CP is a propionyl substituted cellulose ester; CPNp isa propionyl, naphthoyl substituted cellulose ester; CPBz means apropionyl, and benzoyl substitute cellulose ester; DCE isdichloroethane; DCM is dichloromethane; DEP is diethyl phthalate; DMACis dimethylacetamide; DMSO is dimethyl sulfoxide; DMSO-d₆ meansperdeuterated dimethyl sulfoxide; DS_(Ar) is degree of substituted ofaryl-acyl (DS_(Ar) and DS_(Ch) are used interchangeably); DS_(Ch) isdegree of substitution of the chromophore-acyl substituent; DS_(OH) isdegree of substitution of hydroxyl; DS_(Np) is degree of substitution ofnaphthoyl; DSBz is degree of substitution of benzoyl; eq isequivalent(s); EX or Ex is example(s); g means grams; h is hour; Int isintermediate; iPrOH is isopronanol; L is liter; MEK is methyl ethylketone; MeOH is methanol; mg means milligram; MIPK is methyl isopropylketone; min is minute(s); mL means milliliter; NMI is N-methylimidazole;NMR is nuclear magnetic resonance; NpCl is 2-naphthoyl chloride; P ispropionyl; POH is propionic acid; Pv is pivaloyl; PvCl is pivaloylchloride; Pyr is pyridine; rt is room temperature; TPP is triphenylphosphate; wt % is weight percent; F is furan-2-carbonyl; T isthiophene-2-carbonyl; BFC is benzofuran-2-carbonyl; BZT isbenzo[b]thiophene-2-carbonyl; BZTA is benzo[d]thiazole-2-carbonyl BZOAis benzo[d]oxazole-2-carbonyl; NMP is 1-methyl-1H-pyrrole-2-carbonyl;MCA is (E)-methyl 3-(4-(chlorocarbonyl)phenyl)-2-cyanoacrylate; CThA is(E)-2-cyano-3-(thiophen-2-yl)acryloyl; TCA is(E)-2-cyano-3-(p-tolyl)acryloyl; NapNap is6-(chlorocarbonyl)naphthalen-2-yl 2-naphthoate; Bpc is[1,1′-biphenyl]-4-carbonyl; BzBz is 4-(chlorocarbonyl)phenyl benzoate;TMB is 3,4,5-trimethoxybenzoylfuran-2-carbonyl; CMPA is(E)-2-cyano-3-(4-methoxyphenyl)acryloyl; TPB is4-(thiophen-2-yl)benzoyl; BTB is 4-(benzo[d]thiazol-2-yl)benzoyl; BOB is4-(benzo[d]oxazol-2-yl)benzoyl.General Procedure for the Synthesis of the Regioselective CelluloseEsters IntermediatesPreparation of Intermediate 1: To a 4-neck 2 L jacketed flask, undernitrogen with overhead stirring and a bottom valve, was added iPrOH (259g). The jacket was set at 43° C. To the reactor was added Eastman™ CAP482-20 (60 g) through a bent funnel directing the material into thevortex. The slurry was stirred for 10 min. To the slurry was addedN₂H₄.H₂O (18.1 g, 1.90 eq) in AcOH (4.52 g, 0.40 eq) and DMSO (259 g).The reaction mixture was stirred for 24 h. The dope was precipitated bythe addition of water to afford the product as a white solid. The solidswere filtered on a frit and washed with copious amounts of water. Theproduct was transferred to an aluminum pan and dried in vacuo at 55° C.for two days. The product was analyzed by ¹H NMR, ¹³C NMR to determinethat the DS_(Pr)=1.19 and DS_(OH)=1.81.Preparation of Intermediate 2: In a variation of Intermediate 1, 1.70 eqof hydrazine monohydrate was used. Pyridine replaced the iPrOH and DMSOsolvents, and acetic acid was replaced with propionic acid (0.1 eq) andthe reaction temperature was set at 50° C. to give Intermediate 2 whichwas similar to Intermediate 1: DS_(Pr)=1.15 and DS_(OH)=1.85.Preparation of Intermediate 3: CPPv: To a 1 L, 4-neck jacketed resinkettle reaction flask under nitrogen with overhead mechanical stirringwas charged anhydrous dimethylacetamide (DMAC, 6.27 mol) andN-methylimidazole (NMI, 1.23 mol). To the mixture was added withstirring CP (0.288 mol) from Step 1 using a bent funnel to direct thepowder into the vortex. The mixture was stirred 2 hrs at 35° C. toafford a homogeneous mixture. To the dope was added pivaloyl chloride(0.44 mol eq to CP) in DMAC (0.194 mol) dropwise over 25 minutes. Thereaction mixture was stirred at 35° C. for 5 hours. Thecellulose-propionate-pivaloate (aka CP-Pv) product was precipitated bypouring the reaction mass into 4 L of water with homogenization toafford a white solid. The solids were collected in a polypropylene weavebag and continuously washed 6 hrs with deionized water. The washedproduct while still in the closed bag was centrifuged to remove excesswater and then the product was transferred to a glass crystallizationdish and dried in a vacuum oven at 55° C. and −22 in. Hg overnight. Theproduct was analyzed by ¹H NMR and ¹³C NMR to determine theDS_(Pr)=1.19, DS_(Pv)=0.38, and DS_(OH)=1.43.

Table 1 provides a list of cellulose propionates synthesized along withthe equivalents N₂H₄.H₂O, N₂H₄.H₂O solvent used, weight percent polymer,acid (acetic acid or propionic acid), reaction time, and reactiontemperature.

TABLE 1 Rxn Rxn N₂H₄•H₂O Wt % Eq time temp Int Solvent polymer N₂H₄•H₂OEq Acid (h) (° C.) 3 Pyr 9.6 1.60 0.20 18 70 (POH) 4 Pyr 9.7 1.60 0.2024 25 (POH) 5 Pyr 15 1.60 0.20 19.5 50 (AcOH) 6 Pyr 15 1.50 0.20 18 50(POH) 7 DMSO/ 10 1.90 0.40 24 40 iPrOH (AcOH) 8 Pyr 8.4 1.70 0.1  24 50(POH) 9 DMSO/ 10 1.83 0.40 20 43 iPrOH (AcOH) 10 Pyr 12.4 1.63 1.60 2450 (POH) 11 Pyr 13.4 1.60 1.60 23 50 (POH) 12 DMSO/ 10 1.90 0.40 24 43iPrOH (AcOH)

Table 2 provides the degree of substitution for the hydroxyl, and theC2, C3, and C6 degree of substitution for propionyl for Int 2-12 asdetermined by ¹H and ¹³C NMR.

TABLE 2 Int DS_(OH) C2DS_(Pr) C3DS_(Pr) C6DS_(Pr) 2 1.81 ND ND ND 3 1.890.26 0.27 0.65 4 1.84 0.26 0.29 0.62 5 1.90 0.27 0.28 0.63 6 1.81 0.260.33 0.64 7 1.86 0.24 0.28 0.60 8 1.86 0.26 0.33 0.62 9 1.81 0.27 0.320.57 10 1.84 0.28 0.32 0.65 11 1.87 0.24 0.31 0.57 12 1.90 0.23 0.290.58Preparation of Example 1 (CPPvNp): To a 500 mL, 4-neck flask undernitrogen with mechanical stirring was added DMAC (177 g) and theIntermediate 1 (17.47 g). To the mixture was added NMI (38.66 g), andthe mixture was stirred overnight at rt to afford a dope. To the dopewas added PvCl (3.01 g, 0.32 eq) in DMAC (3.01 g), dropwise over 20 min,and the mixture was stirred at rt for 2 h. To the reaction mixture wasadded NpCl (21.28 g, 1.43 eq) in DMAC (21.28 g), dropwise over 30 min.The reaction mixture was stirred for 12 h. The dope was precipitated bypouring slowly into 1.5 L of water using a high speed homogenizer toprovide turbulent mixing, thereby affording a white solid. The solid wasisolated by vacuum filtration then re-slurried with water (4×) and withiPrOH (2×) to give the title compound. The product was dried in vacuo at55° C. overnight. Example 1 was analyzed by ¹H NMR, ¹³C NMR to determinethe DS_(Pr)=1.18, DS_(Pv)=0.27; DS_(Np)=1.20; and DS_(OH)=0.35.

Following the aforementioned procedures, the following examples in Table3 were prepared by varying the solvent, equivalents of PvCl and ChCl(BzCl or NpCl). Additionally, the intermediate used to synthesize theintermediate and the degree of substitution is also provided.

TABLE 3 Eq ChCl Eq (Ch = Bz/ EX # Int Product Solvent PvCl Np/Bt)DS_(Ac) DS_(Pr) DS_(Pv) DS_(Ch) 2 3 CPBz Pyr 0.00 1.9 0.02 1.16 0.001.80 (BzCl) 3 4 CPBz Pyr 0.00 1.9 0.00 1.16 0.00 1.79 (BzCl) 4 5 CPBzPyr 0.00 1.9 0.00 1.12 0.00 1.72 (BzCl) 5 6 CPNp Pyr 0.00 1.6 0.00 1.220.00 1.56 (NpCl) 6 8 CPNp Pyr 0.00 1.6 0.00 1.15 0.00 1.61 (NpCl) 7 7CPPv DMAC/ 0.40 0.0 0.00 1.15 0.36 0.00 NMI 8 8 CPPvBz DMAC/ 0.45 1.40.00 1.14 0.41 1.31 NMI (BzCl) 9 9 CPPvBz Pyr 0.40 1.4 0.00 1.19 0.331.33 (BzCl) 10 9 CPPvNp DMAC/ 0.415 0.3 0.00 1.19 0.41 1.25 NMI (NpCl)11 9 CPPvNp DMAC/ 0.42 1.2 0.00 1.19 0.37 1.23 NMI (NpCl) 12 10 CPPvNpDMAC/ 0.42 1.2 0.00 1.17 0.38 1.17 NMI (NpCl) 13 10 CPPvNp Pyr 0.40 1.20.00 1.12 0.36 1.22 (NpCl) 14 11 CPPvNp Pyr 0.40 1.2 0.00 1.12 0.37 1.18(NpCl) 15 10 CPPvNp Pyr 0.40 0.6 0.00 1.17 0.36 0.60 (NpCl) 16 10 CPPvNpPyr 0.40 0.8 0.00 1.19 0.36 0.80 (NpCl) 17 10 CPPvNp Pyr 0.40 0.8 0.001.19 0.36 0.80 (NpCl) 18 7 CPPvNp DMAC/ 0.22 1.4 0.00 1.16 0.2 1.29 NMI(NpCl) 19 7 CPPvNp DMAC/ 0.30 1.4 0.00 1.15 0.25 1.3 NMI (NpCl) 20 12CPPvNp DMAC/ 0.32 1.4 0.00 1.1 0.29 1.31 NMI (NpCl) 21 12 CPPvNp DMAC/0.32 1.4 0.00 1.1 0.29 1.31 NMI (NpCl) 22 12 CPPvNp DMAC/ 0.43 1.2 0.001.11 0.38 1.18 NMI (NpCl) 23 12 CPPvNp DMAC/ 0.42 1.3 0.00 1.12 0.381.29 NMI (NpCl) 24 12 CPPvNp DMAC/ 0.43 1.3 0.00 1.11 0.41 1.23 NMI(NpCl) 25 1 CPPvBt DMAC/ 0.32 1.4 0.00 1.11 0.32 1.06 NMI (BtCl) 68 1CPPvNP DMAC/ 0.43 1.2 0.00 1.1 0.4 1.2 NMI (NpCl)Preparation of Example 26 (CPPvF): To a dry 250 mL Erlenmeyer flaskequipped with a magnetic stir bar and capped with septum and insertedwith N₂ was charged anhydrous dimethylacetamide (DMAC, 1.53 mol) andN-methylimidazole (NMI, 0.164 mol). To the mixture was added withstirring CP-Pv (0.0.034 mol) from Step 2. The mixture was stirred 2 hrsat RT to afford a homogeneous mixture. To the dope was added withstirring furanoyl chloride (0.114 mol eq to CP-Pv) in DMAC (0.126 mol)over 1 minute. The reaction was stirred under a N₂ blanket at roomtemperature for 24 hours. The product was precipitated by pouring into1.2 L of methanol with homogenization to afford a white solid (akaCP-Pv-F). The solids were collected in a polypropylene weave bag andwashed with methanol (2×800 mL). The washed product while still in theclosed bag was transferred to a wash station and continuously washedwith deionized water for 6 hours. The product was centrifuged to removeexcess water and then the product was transferred to a glasscrystallization dish and dried in a vacuum oven at 55° C. and −22 in. Hgovernight. The product was analyzed by 1H NMR, ¹³C NMR and for opticalproperties.

The examples in Table 4 were synthesized by adapting the procedure forthe synthesis of Ex. 26. The equivalents of Ch-Cl used to synthesizeeach example is provided. Each compound was characterized to determinethe degree of substitution for the Pr, Pv, Ch and OH substituents.

TABLE 4 Eq. Eq. CP-Pv-Ch Ex # PvCl Ch-COX Product DS_(Pr) DS_(Pv)DS_(Ch) DS_(TOT) DS_(OH) 26 0.43 1.02 CPPvF 1.2 0.41 1.01 2.62 0.39 270.43 0.99 CPPvF 1.2 0.41 1.0 2.63 0.39 28 0.48 1.18 CPPvF 1.19 0.45 1.052.69 0.31 29 0.48 1.37 CPPvF 1.22 0.46 1.25 2.93 0.07 30 0.44 1.00 CPPvF1.22 0.39 0.84 2.45 0.55 31 0.44 0.90 CPPvF 1.22 0.4 0.77 2.39 0.61 320.44 1.14 CPPvF 1.19 0.39 1.04 2.62 0.38 33 0.44 1.06 CPPvF 1.2 0.38 0.92.48 0.52 34 0.44 1.19 CPPvF 1.19 0.4 1.01 2.6 0.4 35 0.44 1.12 CPPvF1.2 0.41 0.96 2.57 0.43 36 0.44 1.09 CPPvF 1.2 0.38 0.94 2.52 0.48 370.44 1.12 CPPvF 1.21 0.38 0.96 2.55 0.45 38 0.43 1.00 CPPvBFC 1.2 0.431.02 2.65 0.35 39 0.48 1.33 CPPvBFC 1.22 0.45 1.24 2.91 0.09 40 0.44 1.0CPPvBFC 1.19 0.4 0.83 2.42 0.58 41 0.44 0.94 CPPvBTB 1.21 0.4 0.92 2.530.47 42 0.48 1.33 CPPvBzBz 1.23 0.46 1.18 2.87 0.13 43 0.48 1.22 CPPvBZT1.22 0.46 1.12 2.8 0.20 44 0.44 1.00 CPPvBZT 1.19 0.4 0.74 2.33 0.67 450.44 1.00 CPPvBZT 1.19 0.38 0.81 2.38 0.62 46 0.44 1.00 CPPvBZT 1.19 0.40.83 2.42 0.58 47 0.44 0.99 CPPvBZT 1.19 0.4 0.80 2.39 0.61 48 0.44 0.94CPPvBZT 1.19 0.4 0.74 2.33 0.67 49 0.44 0.97 CPPvBZT 1.19 0.41 0.79 2.390.61 50 0.44 0.91 CPPvBZT 1.21 0.38 0.74 2.33 0.67 51 0.44 0.91 CPPvBZT1.21 0.38 0.66 2.25 0.75 52 0.44 0.90 CPPvBZT 1.21 0.38 0.7 2.29 0.71 530.44 1.06 CPPvMCA 1.2 0.36 0.86 2.42 0.58 54 0.48 0.97 CPPvMCA 1.19 0.440.76 2.39 0.61 55 0.44 0.88 CPPvMCA 1.19 0.4 0.7 2.29 0.71 56 0.44 1.01CPPvNMP 1.2 0.38 0.35 1.93 1.07 57 0.44 1.02 CPPvNMP 1.19 0.4 0.62 2.210.79 58 0.44 1.51 CPPvNMP 1.19 0.4 0.73 2.32 0.68 59 0.48 1.18 CPPvT1.23 0.46 1.04 2.73 0.27 60 0.44 0.95 CPPvT 1.22 0.4 0.77 2.39 0.61 610.44 1.07 CPPvT 1.21 0.39 0.93 2.53 0.47 62 0.44 1.03 CPPvT 1.22 0.370.91 2.5 0.50 63 0.44 1.00 CPPvTMB 1.19 0.4 0.73 2.32 0.56 64 0.44 1.10CPPvTMB 1.19 0.38 0.86 2.43 0.57 65 0.44 1.06 CPPvTCA 1.20 0.38 0.732.31 0.69 66 0.44 1.06 CPPvTCA 1.21 0.40 0.76 2.37 0.63 67 0.44 1.07CPPvTCA 1.21 0.41 0.73 2.35 0.65

Table 5 provides the degree of substitution values were determined by¹³C NMR. The normalized or adjusted degree of substitution wascalculated by multiplying the ratio of the total acyl as determined by¹³C NMR and the total acyl as determined by ¹H NMR.

TABLE 5 Experimental Degree of Normalized Degree of SubstitutionSubstitution C2 C3 C6 ¹³C acyl ¹³C adj adj adj adj ¹³C adj ¹³C Ex # AcylAcyl Acyl Total DS_(OH) Ac2 Ac3 Ac6 acyl DS_(OH) Int-1 0.25 0.32 0.571.14 1.86 0.26 0.33 0.60 1.19 1.81 Int-2 0.27 0.35 0.60 1.22 1.78 0.250.33 0.57 1.15 1.85  Int-12 0.23 0.29 0.58 1.10 1.98 0.23 0.29 0.58 1.101.98 7 0.31 0.41 0.79 1.51 1.49 0.31 0.41 0.79 1.51 1.49 12 0.98 0.770.99 2.74 0.26 0.97 0.76 0.98 2.72 0.28 13 0.99 0.68 0.98 2.65 0.35 1.010.69 1.00 2.70 0.30 21 0.96 0.72 0.96 2.63 0.37 0.99 0.74 0.98 2.71 0.2922 0.96 0.68 0.98 2.62 0.38 0.98 0.69 1.00 2.67 0.33 23 0.98 0.80 0.962.74 0.26 1.00 0.82 0.98 2.80 0.20 24 0.98 0.70 0.96 2.65 0.35 1.02 0.731.00 2.73 0.27

Table 6 provides the degree of substitutions for Pv and Np at C2, C3 andC6 along with the total degree of substitution for PV and Np of thecellulose ester backbone as determined by ¹³C NMR.

TABLE 6 DS_(Pv) DS_(Np) Ex # C2DS_(Pv) C3DS_(Pv) C6DS_(Pv) TotalC2DS_(Np) C3DS_(Np) C6DS_(Np) Total 7 0.06 0.08 0.22 0.36 12 0.06 0.080.24 0.38 0.65 0.35 0.15 1.15 13 0.06 0.08 0.22 0.36 0.71 0.29 0.22 1.2221 0.04 0.01 0.20 0.29 0.72 0.44 0.20 1.36 22 0.06 0.05 0.24 0.38 0.690.35 0.18 1.22 23 0.06 0.05 0.24 0.38 0.71 0.48 0.16 1.35 24 0.06 0.050.26 0.41 0.73 0.39 0.16 1.28

Using the data provided in Table 6, the values in Table 7 werecalculated. The data show that the aryl-acyl group is favored on the C2and C3 positions over C6 position. Additionally, the C2 position isfavored over the C3 position.

TABLE 7 (C2DS_(Np) + C3DS_(Np)) − C2DS_(Np) − Ex # C6DS_(Np) C3DS_(Np)21 1.0 0.3 22 0.9 0.3 23 1.0 0.2 24 1.1 0.3General Procedure for Film Casting

A solvent (DCM, 10% MeOH in DCM, 10% DCE in DCM, MEK, or MIPK) and theregioselective cellulose ester (10 wt %) and optionally a plasticizer(10 wt %, DEP or TPP) were mixed to make a dope. Then, films were castonto glass using a knife applicator and dried either at rt, in the caseof a DCM based dope, or at 85° C. in a forced air oven for 10 min. fordopes made from MEK and MIPK based dopes. The cast films were annealedat 100° C. and 120° C. in a forced air oven for 10 min each. Thethickness of the films were measured using a Metricon Prism Coupler 2010(Metricon Corp.). The birefringence and retardations were measured usinga M-2000V Ellipsometer (J. A. Woollam Co.).

Preparation of EX 25.1: A dope of Ex 25 (10 wt %), TPP (10 wt %), 10%MeOH in DCM was used to cast a film (11.9 μm). Δn=0.006 (589 nm), R_(th)[450 nm]/R_(th)[550 nm]=1.2 (dispersion); R_(th)=0.92 (650 nm/550 nm).

Table 8 provides casting results for the compounds of this application.The solvents used to make the dope is provided along with theplasticizer used. The dopes were used to prepare the films, and thebirefringence and thickness were measured. The birefringence were takenusing a wavelength of 589 nm. The thickness of the films were measuredusing a Metricon Prism Coupler 2010 (Metricon Corp.). The retardationswere measured using a M-2000V Ellipsometer (J. A. Woolam Co.). The hazeand b* measurements were made using a HunterLab Ultrascan VIScolorimeter in diffused transmittance mode (1 inch diameter port). Inthe case of dopes, a 1 cm path length cell was used. For dope b* andhaze, 10 measurements were taken, and the average was reported.

TABLE 8 Film Thickness R_(th) % Haze Film # Solvent 10 wt % Pz Δn(589nm) (μm) (nm) b* (film) 1.1 MEK TPP 0.0066 13.07 86.6 0.27 0.13 3.1 DCMDEP 0.0076 16.59 126.8 — — 3.2 DCM DEP 0.0065 12.36 80 0.69 0.50 3.3 DCMDEP 0.0070 14.96 104.0 0.75 0.80 (10.7 wt %) 4.1 DCM/MeOH TPP 0.00847.54 63.1 0.29 0.27 (9:1) 4.2 DCM/MeOH TPP 0.0076 7.27 55.1 0.28 0.14(9:1) 5.1 DCM/DCE TPP 0.0128 13.79 176.8 0.53 0.81 (91:9) 5.2 MEK TPP0.0084 13.66 115.3 0.34 0.31 7.1 DCM TPP 0.0118 8.1 MEK TPP 0.0067 12.5684.5 0.35 0.28 9.1 DCM TPP 0.0064 17.76 113.5 0.59 0.46 10.1 MEK TPP0.0107 13.83 148.6 0.45 0.21 11.1 MEK TPP 0.0098 10.40 102.0 0.34 0.2411.2 MEK TPP 0.0101 11.43 114.9 0.32 0.11 12.1 MEK TPP 0.0076 12.72 97.113.1 DCM/MeOH TPP 0.0126 19.35 244.3 0.69 0.52 (97:3) 13.2 DCM/MeOH TPP0.0141 12.84 180.4 0.60 0.76 (97:3) 13.3 MEK TPP 0.0091 10.52 95.8 0.340.19 14.1 MEK TPP 0.0092 8.96 82.3 0.28 0.19 14.2 MEK TPP 0.0108 7.8184.4 0.29 0.20 14.3 MEK — 0.0086 8.07 69.6 0.30 0.15 14.4 MIPK — 0.00879.29 80.7 0.30 0.12 15.1 DCM/MeOH TPP 0.0032 14.04 44.3 0.32 0.42 (97/3)16.1 DCM TPP 0.0062 11.60 72.1 0.33 0.32 16.2 DCM/MeOH TPP 0.0085 18.47156.2 0.36 0.41 (9:1) 18.1 DCM/MeOH TPP 0.0093 13.61 126.8 0.33 0.63(97:3) 19.1 MEK TPP 0.0066 12.42 81.7 20.1 MEK TPP 0.0070 13.44 94.30.70 0.82 21.1 MEK TPP 0.0076 9.38 71.1 0.30 0.14 22.1 MEK TPP 0.007713.89 106.4 0.28 0.40 23.1 MEK TPP 0.0096 12.38 118.9 0.50 0.55 24.1 MEKTPP 0.0091 8.91 81.1 0.28 0.25Preparation of Bilayer Films by Solution CastPolymer Dope Preparation and Film Casting Procedure (Using EastmanVisualize™ Material 234 (“VM234”) Films as an Example)

VM234 polymer is mixed at 12 wt % in solution with 13% MeOH in DCM and10 wt % triphenylphosphate (TPP) as plasticizer based on solids (VM234and TPP combined). Plasticizer types can be adjusted based on desiredfilm strength and optical properties. A typical recipe uses

54 g VM234

6 g TPP (or other plasticizer)

390 g solvent (13% MeOH in DCM).

Dopes are made in a 16 oz wide mouth jar and placed on a roller at roomtemperature for 12-24 hours or until fully in solution. The polymerneeds to be completely dissolved with no “fish eyes” (i.e., gels)present in the solution. When ready to cast, the dope is removed fromthe roller and allowed to sit until all bubbles have left solution.

Films are cast onto a glass plate using a GardCo Automatic DrawdownMachine II set to a speed of 3.5 and a 10-inch GardCo adjustablemicrometer film applicator with stainless steel blade set to a 30 mildrawdown gap from the surface of the glass (targeting a 60 μm film). Thedope is poured as a puddle between the “feet” of the casting blade. TheAutomatic Drawdown Machine pushes the casting blade over the dope,smoothing it out to the desired thickness. A non-contacting cover isimmediately placed over the cast dope to slow down the solventevaporation rate and prevent bubble formation. At the end of this time,the cover is propped open approximately 1 cm. for 15 minutes, at whichpoint the cover is completely removed and the film is allowed to dryuncovered for an additional 15 minutes.

Once the film is dry, it is removed from the casting plate using a razorblade and placed between two sheets of paper. A heavy rectangular weightis placed on top of the sheet of film to prevent curling. The film cansit under the weight for up to a week.

The sheet of film is then cut into six smaller films for annealing,measuring, and stretching. The size of the film is determined by thetype of stretching. For uniaxial (unconstrained) stretching, the filmsare 8.8 cm wide×12 cm long. Films for constrained stretching are 12cm×12 cm.

The cut films are placed individually between two thin aluminum squareswith a 3 in×3 in square cut out in the middle. The entire film iscovered by the aluminum with the exception of the 3 in×3 in square inthe middle of the film; it is this portion of the film on which all themeasurements are run. The aluminum plates are secured with four owlclips, one at each corner of the film.

Secured films are then stacked on a cookie sheet for annealing.Typically, six films are stacked per ‘cookie sheet’, in two stacks ofthree films. The cookie sheet of films is then placed in a Blue M ovenset to 100° C. for 10 minutes, then immediately moved into a Blue M ovenset to 120° C. for an additional 10 minutes of annealing. After theannealing process is complete, the films cool to room temperature andare then removed from the aluminum plates before being measured.

Optical properties for each film are measured using a J.A. Woollan Co.,Inc. spectroscopic ellipsometer with the JAW Co. Retardance MeasurementProgram and corresponding V.A.S.E. software for Windows. The color (B*)and haze for each film is measured using a HunterLab Ultrascan VIScolorimeter in diffused transmittance mode. The thickness of the filmsis measured using a handheld Positector 6000.

By adapting the procedures for preparation of films, the following filmsin Table 9 were prepared.

TABLE 9 DSUV Optical Data R_(e) R_(th) Film CE d (589 nm) (589 nm)R_(th) # Ex # CPPvCh (μm) (nm) (nm) (589 nm)/d 26.1 26 CPPvF 9.4 0.113.7 1.4 27.1 27 CPPvF 10.3 0.0 15.4 1.5 28.1 28 CPPvF 8.9 0.5 23.0 2.629.1 29 CPPvF 10.2 1.9 56.5 5.5 30.1 30 CPPvF 10.5 0.1 1.9 0.2 31.1 31CPPvF 9.8 −0.1 −4.9 −1.3 32.1 32 CPPvF 9.1 0.1 18.3 2.0 33.1 33 CPPvF12.5 0.4 6.5 0.5 34.1 34 CPPvF 9.5 −0.1 29.9 3.1 35.1 35 CPPvF 8.6 −0.219.7 2.3 36.1 36 CPPvF 6.4 0.0 13.2 2.1 37.1 37 CPPvF 6.7 0.4 18.3 2.538.1 38 CPPvBFC 10.6 0.2 41.5 3.9 39.1 39 CPPvBFC 11.1 1.8 77.6 7.1 40.140 CPPvBFC 9.2 0.1 22.6 2.5 41.1 41 CPPvBTB 10.2 0.2 47.1 4.6 42.1 42CPPvBzBz 0.0 −24.3 43.1 43 CPPvBZT 6.2 0.2 43.8 7.1 44.1 44 CPPvBZT 10.6−0.2 42.2 4.0 45.1 45 CPPvBZT 12.9 0.0 56.0 4.3 46.1 46 CPPvBZT 10.7 1.162.1 5.8 47.1 47 CPPvBZT 9.3 1.7 49.7 5.3 48.1 48 CPPvBZT 10.9 0.5 45.14.1 49.1 49 CPPvBZT 3.3 0.7 15.8 4.8 50.1 50 CPPvBZT 6.1 0.0 22.2 3.651.1 51 CPPvBZT 6.8 0.5 18.6 2.7 52.1 52 CPPvBZT 7.0 0.1 23.8 3.4 53.153 CPPvMCA 11.7 1.5 64.7 5.6 54.1 54 CPPvMCA 6.7 0.0 34.3 5.1 55.1 55CPPvMCA 8.6 0.2 30.7 3.6 56.1 56 CPPvNMP 9.4 0.0 −43.2 −4.6 57.1 57CPPvNMP 10.5 0.2 −9.1 −0.9 58.1 58 CPPvNMP 10.8 −0.1 3.8 0.3 59.1 59CPPvT 10.9 −0.1 48.1 4.4 60.1 60 CPPvT 9.4 0.4 17.8 1.9 61.1 61 CPPvT11.2 0.4 35.9 3.2 62.1 62 CPPvT 12.6 0.1 38.9 3.1 63.1 63 CPPvTMB 9.30.2 15.0 1.6 64.1 64 CPPvTMB 9.7 0.0 24.8 2.6 65.1 65 CPPvTCA 5.4 1.023.3 4.33 66.1 66 CPPvTCA 4.7 4.6 19.1 4.2 67.1 67 CPPvTCA 6.9 0.3 40.55.9

TABLE 10 CE R_(e)(450 nm)/ R_(e)(650 nm)/ R_(th)(450 nm)/ R_(th)(650nm)/ Film # Ex # R_(e)(550 nm) R_(e)(550 nm) R_(th)(550 nm) R_(th)(550nm) 26.1 26 1.74 0.30 1.22 0.89 27.1 27 0.28 0.24 1.22 0.89 28.1 28 1.011.00 1.14 0.93 29.1 29 1.08 0.94 1.10 0.95 30.1 30 1.06 0.68 2.17 0.4331.1 31 0.63 1.29 0.40 1.29 32.1 32 0.00 0.63 1.17 0.91 33.1 33 0.970.87 1.52 0.74 34.1 34 −1.36 1.22 1.15 0.93 35.1 35 −0.91 1.84 1.18 0.9136.1 36 0.19 0.00 1.21 0.90 37.1 37 1.01 0.94 1.19 0.91 38.1 38 1.050.97 1.12 0.94 39.1 39 1.04 0.89 1.11 0.95 40.1 40 −0.09 1.01 1.16 0.9241.1 41 −1.16 −1.51 1.12 0.94 42.1 42 0.87 0.88 1.05 0.98 43.1 43 0.410.91 1.14 0.94 44.1 44 1.12 0.98 1.21 0.91 45.1 45 1.20 0.44 1.19 0.9246.1 46 1.12 0.91 1.17 0.93 47.1 47 1.11 0.94 1.18 0.92 48.1 48 0.980.97 1.20 0.91 49.1 49 0.93 0.85 1.19 0.92 50.1 50 1.63 −0.74 1.21 0.9151.1 51 −0.09 −0.05 1.28 0.88 52.1 52 0.93 0.86 1.24 0.89 53.1 53 1.190.96 1.13 0.94 54.1 54 0.81 0.72 1.15 0.93 55.1 55 1.00 1.05 1.17 0.9256.1 56 −1.08 0.29 0.96 1.02 57.1 57 0.98 0.28 0.58 1.20 58.1 58 0.910.13 1.90 0.57 59.1 59 0.43 0.18 1.13 0.93 60.1 60 1.03 0.95 1.27 0.8761.1 61 1.09 0.91 1.18 0.92 62.1 62 1.02 0.36 1.18 0.91 63.1 63 1.811.06 1.28 0.87 64.1 64 0.70 −0.06 1.19 0.91 65.1 65 0.44 0.36 1.25 0.9066.2 66 1.23 0.91 1.22 0.91 67.3 67 1.21 1.11 1.23 0.90Bilayer Coatings

The bilayer substrate is cast consistent with the procedures listedabove, using a slightly smaller casting blade (9-inch instead of10-inch).

The coating is doped in a 4 oz wide mouth jar at 8-9 wt % polymer insolvent. Plasticizer is not used in the coating. A typical dope recipemay consist of

-   -   4 g polymer (UV-dye compound)    -   41 g solvent (87/13 DCM/MeOH, or MEK, or consistent with the        solvent system used for the substrate).

To cast the bilayer film, the substrate is first cast and dried. Afterthe allotted drying method and time, a 10-inch GardCo adjustablemicrometer film applicator with stainless steel blade is set to a 1-2mil drawdown gap from the surface of the substrate film. The edges ofthe casting blade rest on the glass outside the edges of the substratefilm (so that the casting blade does not scratch the substrate). Thecoating dope is poured as a puddle on the glass plate above thesubstrate, and the film is cast and dried on top of the substrate usingthe same procedure as the substrate. The films are then prepared in thesame manner as the procedure above.

The thickness of the coating on the bilayered film can be measured usinga Metricon MCU Model 2010 Prism Coupler. First, the refractive index ofthe substrate is measured, then the index is used to calculate thethickness of the coating.

Stretching of Bilayer Films

Turn the nitrogen tanks on. Turn the stretcher on. Prep the samplesusing the designated precision cutter. Set up the test parameters on theinstrument and allow it to preheat to the desired temperature. Load thesample into the clips to be stretched. Using the computer, engage theclips and start the stretching test. Heat the film for 25 seconds in thestretching oven (soak time) before beginning to stretch. Films aregenerally stretched uniaxially (unconstrained) or biaxially(constrained). Uniaxial stretched films are stretched to the ratiospecified based on the original size of the film. Stretching ratios aretypically between 1×1.4 and 1×2.0, such that a film stretched to a ratioof 1×1.4 is 40% longer than its original length. Films are stretched ata rate of 1% per second. After the stretching test is complete, releasethe clips. Using the computer switch, open the clips and then remove thesample. After all samples have been tested for the day, initiate autoshutdown. Turn off the nitrogen tanks and expel/flush the lines. Closenitrogen and air valves on instrument.

Optical Properties of Various Bilayer Films

TABLE 11 Optical Properties of Unconstrained, Machine DirectionStretched Furanoyl Optical Compensation Film CE d R_(e)(589 nm)R_(th)(589 nm) R_(e)(450 nm)/ R_(e)(650 nm)/ Film # Ex # (μm) (nm) (nm)R_(e)(550 nm) R_(e)(550 nm) 35.2 35 68.0 146.2 −78.68 0.88 1.06 32.2 3274.0 113 −67 0.82 1.10 32.3 32 72.0 111 −64 0.82 1.09 32.4 32 77.0 110−65 0.83 1.09 35.3 35 63.0 113 −81 0.84 1.09 32.5 32 68.0 129 −75 0.861.08 28.2 28 84.0 125 −69 0.86 1.08 35.4 35 62.0 110 −85 0.86 1.08 37.237 66.0 133.19 −96.54 0.86 1.07 32.6 32 72.0 125 −73 0.86 1.07 32.7 3268.0 136 −77 0.86 1.07 32.8 32 62.0 130 −74 0.87 1.07 28.3 28 84.0 120−73 0.87 1.07 35.5 35 54.0 116 −73 0.87 1.07

TABLE 12 Optical Properties of Unconstrained Stretched, MachineDirection Benzothiophenoyl Optical Compensation Film CE d R_(e)(589 nm)R_(th)(589 nm) R_(e)(450 nm)/ R_(e)(650 nm)/ Film # Ex # (μm) (nm) (nm)R_(e)(550 nm) R_(e)(550 nm) 49.2 49 62 111 −77 0.81 1.09 44.1 44 64 109−76 0.82 1.09 49.3 49 65 113 −82 0.83 1.09 44.3 44 59 109 −96 0.85 1.0749.4 49 62 137 −86 0.87 1.06 49.5 49 57 130 −93 0.88 1.06 44.4 44 66 139−81 0.88 1.06 44.5 44 60 128 −87 0.87 1.07 49.6 49 62 137 −86 0.87 1.0649.7 49 64 144 −101 0.87 1.06 44.6 44 58 133 −81 0.87 1.06

TABLE 13 Optical Properties of 45° Stretched Optical Compensation CE dR_(e)(589 nm) R_(th)(589 nm) R_(e)(450 nm)/ R_(e)(650 nm)/ Ex # Ex #(μm) (nm) (nm) R_(e)(550 nm) R_(e)(550 nm) 36.2 36 114 150.92 −190.310.88 1.06 50.2 50 112 150.65 −117.35 0.86 1.08 52.2 52 120 154.73−144.79 0.82 1.09 50.3 50 84 141.53 −116.71 0.85 1.07 52.3 52 87 134.03−119.95 0.84 1.07 66.2 66 74 164.04 −122.83 0.88 1.06Procedure for Accessing Film DuctilityPeel Test

-   -   1. Using the Polymer Dope Preparation and Film Casting        Procedure, cast a 10μ thick film on a 4 inch×5.5 inch plate of        glass.    -   2. Using cut resistant gloves and a razor blade, score the film        from the left edge of the film across to the right edge of the        film approximately 1 inch from the top of the film.    -   3. Place the bottom half of a piece of Scotch™ tape across the        top of the bottom piece of film and fold back the tape to        provide a fingerhold.    -   4. Carefully start peeling the film off of the glass slide in a        continuous motion.    -   5. If 80% of the film comes off of the slide in one piece, the        film passes the peel test.        Strength Grading    -   1. Using the Polymer Dope Preparation and Film Casting        Procedure, cast a film on a plate of glass.    -   2. Wearing cut resistant gloves, slide a razor blade under the        corner of the film and begin to remove the film from the glass        plate. Grade the film by how it responds to the act of being        removed.    -   3. The grades are as follows:        -   a. Excellent—The film comes up in one or two big pieces        -   b. Good—The film comes up in several medium to big pieces        -   c. Bad—The film comes up in a lot of small pieces        -   d. Poor—The film comes up in tiny or shredded pieces.

Film 68.1 was prepared from Ex 68. Films A-B were prepared fromcellulose esters having the degree of substitutions for propionyl,pivaloyl, naphthoyl, and hydroxyl as shown in Table 14. The data inTable 14 shows that a film having a DS_(OH) of less than 0.16 fail thefilm strength and Peel test.

TABLE 14 Compositions that produce ductile and non- ductile RACE C+optical compensation films Passed DS of CE Thickness Film Peel Film #DS_(Pr) DS_(Pv) DS_(Np) DS_(OH) R_(th)/d (μm) Strength Test 68.1 1.0-1.20.37-0.41 1.19-1.25 0.16-0.3 8.0-8.7 12-11.5 Good Yes A 1.18 0.42 1.190.21 9.1 11 Good Yes B 1.19 0.41 1.24 0.16 10 10 Good Yes C 1.16 0.381.32 0.14 11.5 8.7 Bad No

Claims not Limited to Disclosed Embodiments

Forms of the invention described above are to be used as illustrationonly, and should not be used in a limiting sense to interpret the scopeof the present invention. Modifications to the embodiments, set forthabove, could be readily made by those skilled in the art withoutdeparting from the spirit of the present invention.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of thepresent invention as it pertains to any apparatus not materiallydeparting from but outside the literal scope of the invention as setforth in the following claims.

We claim:
 1. A film comprising a regioselectively substituted celluloseester comprising: (a) a plurality of chromophore-acyl substituents; (b)a plurality of pivaloyl substituents, and (c) a plurality of an(C₁₋₆)alkyl-acyl substituents, wherein the cellulose ester has ahydroxyl degree of substitution (“DS_(OH)”) in the range of from 0 to0.9, wherein the cellulose ester has a pivaloyl degree of substitution(“DS_(Pv)”) in the range of from 0.1 to 1.2, wherein the cellulose esterhas a chromophore-acyl degree of substitution (“DS_(Ch)”) in the rangeof from 0.5 to 1.6, and wherein the regioselectivity is such that thesum of the chromophore-acyl degree of substitution at C2 and C3(“C2DS_(Ch)” and “C3DS_(Ch)”) minus the chromophore-acyl degree ofsubstitution at C6 (“C6DS_(Ch)”) is between 0.5 and 1.6, wherein thechromophore-acyl is chosen from

 wherein the aryl is a (C₆)aryl, and wherein the aryl is unsubstitutedor substituted by 1-5 R¹; or

 wherein the heteroaryl is a 5- to 10-membered ring having 1-4heteroatoms chosen from N, O or S, and wherein the heteroaryl isunsubstituted or substituted by 1-5 R¹, wherein each R¹ is independentlychosen from (C₁₋₆)alkyl; halo(C₁₋₆)alkyl; (C₆₋₂₀)aryl-CO₂—; (C₆₋₂₀)aryl;(C₁₋₆)alkoxy; halo(C₁₋₆)alkoxy; halo; 5- to 10-membered heteroarylhaving 1-4 heteroatoms chosen from N, O, or S; or


2. The film of claim 1 wherein the film has a birefringence (“Δn”)between 0.001 and 0.020 as measured at a wavelength of 589 nm.
 3. Thefilm of claim 2 having a percent haze of less than 1.0.
 4. The film ofclaim 3, wherein the thickness of the film is in the range of from 1 μmto 20 μm.
 5. The film of any one of claims 1-4 wherein the film is a +C,−C, +A, or −A film.
 6. The film of claim 5, wherein the film is 45degree, uniaxially, or biaxially stretched.
 7. A multilayer filmcomprising the film of claim
 1. 8. The multilayer film of claim 7,further comprising another film comprising a cellulose ester, apolycarbonate, a polyester, a polyimide, a cycloolefin polymer, acycloolefin copolymer, or combinations thereof.
 9. The multilayer filmof claim 8, wherein the multilayer film has a thickness in the range of20 μm to 140 μm.
 10. The multilayer film of claim 9, wherein themultilayer film is 45 degree, uniaxially, or biaxially stretched. 11.The multilayer film of any one of claim 7 or 10, wherein the multilayerfilm has a positive in-plane retardation that satisfies the relations of0.7<R_(e)(450)/R_(e)(550)<1 and 1<R_(e)(650)/R_(e)(550)<1.25, whereinR_(e)(450), R_(e)(550), and R_(e)(650) are in-plane retardations at thelight wavelengths of 450 nm, 550 nm, and 650 nm, respectively.
 12. Themultilayer film of any one of claim 7 or 10, wherein the multilayer filmhas an in-plane retardation (R_(e)) of 50 to 160 nm at the lightwavelength of 550 nm.
 13. The multilayer film of any one of claim 7 or10, wherein the multilayer film has an out-of-plane retardation (R_(th))of −200 nm to 0 nm at the light wavelength of 550 nm.
 14. A liquidcrystalline display (“LCD”) comprising the film of claim
 1. 15. Acircular polarizer comprising the film of claim
 1. 16. An organic lightemitting diode (“OLED”) display comprising the film of claim 1.